It seems odd to me that upon learning that paladin Danse is a synth, there doesn't appear to be any way to talk with the Railroad or Institute about it. Wouldn't the SRB want you to bring him in for reclamation? Wouldn't the railroad want to help him to escape? It would be neat if we could learn about his past as a synth and the events that led to his original decision to wipe his memory.

Think of it as the Elder testng your comitment to the Brotherhood. Yes you can persuade him not to throw you out of the Brotherhood if you don't kill him, but they'll still fire on him if any Brotherhood patrols see him.

This is how the Brotherhood operate, even Danse will tell you it's the right thing.

No, I understand why Maxon does what he does, but why doesn't the player character have the ability to bring up the issue with other interested parties for alternative solutions?

Paladin Danse is outed as a synth before you reach any "decision points" between the factions, so if I'm on an intitute playthrough why can't I talk to the SRB and get Danse's overide code and relay him into the institute for his factory reset? As an escaped and mindwiped synth, presumably he passed through the Railroad long ago: why can't I talk with them about it? Several synths left voice recordings explaining why they wanted their mind wiped, maybe Danse did as well: playing that recording for Danse (or any other data from his life before the mindwipe) might give him the insight he needs to get him onboard with helping out the railroad.

Exactly the reason why I never could support the BOS.

Danse would automatically attack both groups. In his mind he is apart of BOS, even though he knows he's a synth. he will still follow what the BOS stands for.

And exactly the reason why I joined the BOS. At least they are honest and genuinley believe in their cause, unlike the scumbags in the RR who I gladly killed

That would require Bethesda to actually write something deeper than the front cover

I don't see why his overide code wouldn't be exactly as effective as it is for every other synth you encounter.

As for getting him to support the railroad, as a part of Blind Betrayal you can already convince him that he is a benefit to humanity, that the Brotherhood is thusly wrong to want him dead. From there it's not much of a leap to convince him that ANY synth might have just as much value, and so the Brotherhood is just as wrong to order the destruction of the Railroad.

And how exactly would he ever support when the RR wants to destroy the BOS?

Its unfortunate there isn't a solution to the BoS/Railroad conflict besides utter destruction. The Railroad is all about subtlety: allowing the Brotherhood to BELIEVE the Railroad is destroyed should be enough to satisfy the Brotherhood's desire to "plug the leak". They never have anything but the Sole Survivor's word that the Railroad leadership is dead to begin with, so why aren't I allowed to LIE to them about it?

Actually, there are BOS soldiers right outside the door when you kill the RR, so I think they double check that they're dead instead of simply taking your word.

The only place I found a reference to Danse was in the Synth Retention section on a console.
Which explains where Maxson's people found the info on Danse, if you deliver the tape to them.