Because whether or not he managed to change the Enclave to be somewhat accepting of outsiders his objectives did make sense. Remember that scenario you laid out earlier where the Enclave could grow and expand on the other side of the continent? That's what Autumn is trying to do but if he can recruit the remnants of the population on the East Coast he's not stuck with the tiny little band of survivors the Enclave has devolved into. He's trying to win outside support and make the Enclave a genuine power. Whether that would've worked or not (I don't think it would've) it's still more reasonable than Eden's use of the purifier which is a total waste.
Again though if they wanted to take out the people around them who could possible do such a thing why didn't they focus on actually taking them out instead of indirectly (and slowly) taking them all out by cleansing genetic mutations? Attack the Pentagon with Vertibirds. Launch a pre-emptive strike don't sit around inviting an attack and giving the Brotherhood time to repair Liberty Prime by messing around with Project Purity. Eden's plan isn't to kill those who pose a threat, it's to fulfill the overall Enclave goal of cleansing genetic mutations but on such a small scale that it's pointless. It's like he's forgotten the Enclave does have means of killing people other than the modified FEV.
Prehaps that is becuase Eden was cautious in regards to the capabilities of the Brotherhood to fight back. As much as I hate the Brotherhood in Fallout 3, they did manage to be resourceful and fight off the Enclave. By all accounts, yes, the Enclave should have mopped the floor with the Brotherhood, but frankly, they didn't in the game and while this may be largely a result of issues with Bethesda's writing, the Brotherhood were still able to fight them off at Adams following the Project Purity disaster. There is also the possiblity a full scale attack would have meant the unification of others under the Brotherhood, making this even more complicated.
In regards to Autumn's plans, what was he going to do when he supposedly earned people's loyalty? His ideas are completely incompatiable with the Enclave and would have meant the destruction of everything they stood for (genetic purity). How do you think Enclave citizens would have taken it if they were forced to serve side-by side with people they had been taught from birth were inferior disgusting mutants? It would have been anarchy, to say the least. Its also not what I meant by expansion, I meant expansion through the Enclave's own means, anything else and you basically have a carbon copy of the NCR. And your right, Autumn's plan didn't work, it led to the Enclave's destruction when he tried to hold project purity.
He wasted a significant garrison occupying the Purifier that could've been used to attack the Citadel or simply secure Raven Rock until the airborne virus was ready to go.
As I've said, that was Autumn who commandered those troops, Eden never ordered it. (and if you are referring to the intial occupation, how many troopers were there, like 15?)
I find that difficult to believe. If Autumn had already gone rogue by the initial occupation then why does he listen to Eden's orders at all on the return to Raven Rock? It seems pretty clear that he was occupying the Purifier as the first step in Eden's plan and that Eden only used the Lone Wanderer because he had no other options. It wasn't that he planned for a single covert agent to do the job it's just he had no other resources to call on.
Just because he took the intiative to occupy the base without the President's orders (if that is indeed what happened) that doesn't mean that he "went rogue" and just would've given a big "SCREW YOU!" to Eden right then and there. Autumn's character is obviously very conflicting and confusing (and poorly written) he may have believed he was acting under the Presidents orders, or doing what he would have wanted. If Eden did order the occupation then, it doesn't mean Eden intended to do what Autumn did and hold it against the Brotherhood, maybe step 2 in Eden's plan was to order Autumn to poison the water as soon as the project was operational (or before actually) but Autumn didn't comply (which led to his leaving Raven Rock).
Again though if the Brotherhood stood no chance in a fight attack the Pentagon. If the Brotherhood was a potentially dangerous foe then why invite an attack by sending out eyebots and attacking the Purifier before the virus was even ready to be deployed. This doesn't speak much of Eden's leadership.
The Brotherhood were apparently really surprised when the Enclave showed up so it looks as if those eyebots were largely ignored. The eyebots in the game also don't share a sphere of influence with the Brotherhood (they never meet). The propoganda was intended to prehaps instigate attacks on the Brotherhood and to weaken a possible concerted effort against the Enclave when the attack came.
There is simply nothing to support the idea that the modified FEV is meant to be a precision strike against the Brotherhood. The very nature of the weapon argues against it and makes it pretty clear that Eden has become obsessed with implementing the Enclave's plan in D.C. but without realizing that implementing the plan in D.C. only is completely pointless.
You're right, it is not a precision strike against just the Brotherhood, it is a precision stike against the Supermutants, Outcasts, Talon Company, Regulators, mutant animals, and the Brotherhood. What do you consider to be Eden's plan? All we know for sure is he intended to sabotage the purifier and kill off many possible threats to Enclave operations in the process, everything else was Autumn.
It's hardly speculation that the Enclave should've had access to an airborne version of the virus. The virus was designed to be airborne. It was ready to go by the end of Fallout 2. It makes absolutely zero sense that the Enclave would somehow retain knowledge of the virus without possessing the knowledge to make it airborne when it was an airborne virus while also actually finding it easier to redesign it for deployment in water. Yes a lot of things in Fallout 3 are illogical. Eden's plan is one of them.
See I don't know about you but given the choice between "Eden is incompetent" or believing that the Enclave knew something about the virus, but not enough to make it viable to deploy via air, even though that was the entire purpose of the initial virus, and instead found it easier to redesign a virus initially designed for air into the water I'm gonna go with Eden is incompetent. It's not really surprising that a supercomputer never designed for sentience who based his personality off countless US presidents might not be the most rational leader around and might even be fixated on reclaiming the nation's capital.
Prehaps it makes zero sense but thats apparently what happened. The virus was not well known amongst anyone but the top-tier of the Enclave, somehow, someway, they retained the basic knowledge of how to modify the FEV but not to get it airborne. I would find it hard to believe that a supercomputer which is designed for efficiency would completely ignore a easier solution if it was avaible. Do you think Eden went "Well we got the airborne ready...but naaaaww we'll use the water-based one".?
Whatever you may think of them Autumn's plans revolved around the Purifier for a reason. Eden's plans seem to encompass the Purifier simply because it was needed as a plot point.
Frankly I don't understand this. You are confusing Autumn's plan with Eden's plan. Autumn was the one who held the purifier and lost many men against the Brotherhood onslaught, for no apparent reason (you state yourself his plan would have failed). When I put the virus in the purifier in my game, its a positive outlook for the Enclave, that if anything should tell you something.
Also I have a question for you. Do you think Richardson was a illogical leader?