I support the reasoning behind UASF, but it could be a dangerous experiment if the community is still divided.
I don't think that the community is divided, all community is unanimous in supporting SegWit. I'd not call neither one corrupt chinese with his paid shills the part of the community, nor altcoiner Roger ver.
If we just disregard them, there's no consequence, even if they create their altcoin BTU, noone will support centralized rogercoin with president and secretary.
the problem is that by creating an altcoin like you said, all the hash can go there while reducing the original fork nethash, which is dangerous, because then attack are possible
this si why miners have the upper hand in terms of decision, then you need to find a way to counter this, if you don't want bitcoin to be destroyed by the miners mafia