The Enclave are, again, a bunch of fascist idiots who try to commit mass genocide twice over a butt-hurt encounter with some Super-Mutants and fail both times and get blown up by a ass-kicking gum-chewing tribal who gets PO'd after they kidnapped his tribe and an idiot who stumbles out of a vault giving detailed descriptions of his apparently male middle-aged father.
You have one little error there, mate...
... you seem to have mistaken the Nationalist government of the Enclave... for a Fascist government... which is an entirely different thing altogether. The two are similar, mind... and Fascism draws heavily upon a base of Nationalist sentiment... but the two are quite different both in definition and practice.
Furthermore, you seem hung up on this idea of 'mass genocide'... (which by the by, is redundant)
The Enclave is a nation at war. Their strict laws, radical beliefs, an intolerance for aberrations of genetics are the battlefield.
Out in the wasteland... there are mutations, and viruses, and every kind of predator you can imagine. Some were made by men... others by the twisted evolution of radiation-assisted nature. From the average 'wastelander' human to the ferocious Deathclaw, all of these mutations are absolutely and irrevocably deadly. Wastelanders are erratic and violent... and their mutated DNA, while possibly containing great new secrets of human evolution, cannot be allowed to run rampant.
The Supermutants are abominations of science... the failures of men who lived long ago, and certainly a great force of destruction. Those who are hostile should be eliminated with extreme prejudice... and those who are not hostile should be registers and confirmed as being socialized. The risk of such behemoths ruining the viability of an entire region is no better evidenced than by the example set in Washington D.C.
If stability is to ever be restored... than the threat of rampant mutation, and the threat posed by wildly mutated creatures rauaging the ecosystem, must be reduced and ultimately eliminated. If this means finding a way to reverse ghoulification and the effects of FEV... then that should be an option. But the decision to eradicate them all was one made without ease of mind or clearness of conscience.
It was a poor decision, one which would cost a great many American Citizens their lives... but it was made by a man filled with fear and love. He did what he did not as a monster... or out of bigotry... but because he truly didn't believe that there was any other way to ensure that the human species survived.
Does this excuse him from his actions? Of course not!
Does this mean that the entirety of the Enclave, and all of its citizens, agreed with his decision and actions? Does this account for the many deserters and survivors who have no hostile motivations towards anyone else? The decision to launch a nuclear strike... the full nuclear payload of The United States... falls down to the President. So too did the decision to enact the FEV-Modified bomb which Richardson had created.
His actions are no more representative or indicative of the Enclave as a whole than President Eden's (whom admits, himself, that he was -largely- inspired by Richardson) were. The truth of the matter is that the Enclave is, by and large, an unknown entity. New Vegas and the Remnants are really the first decent look we've gotten at the individuals whom the Enclave makes/made up.
Very few of those folks fit the description you seem to apply to the Enclave. In fact... you say they're cool.
They're the same people you just called idiots... only they lost the war. Do you detect the hypocrisy yet?