I think we've crossed the threshold of "fuck off" being the universal response for anything discussed in Off-Topic at this point.
McCain follows GOP party line --> fuck off
McCain roadblocks his own party's agenda with a dissenting vote, changing the course of history and averting a nightmarish national health care outcome --> fuck off
NeoGAF user praises McCain for saving the ACA --> fuck off
NeoGAF user praises McCain for saving the ACA, but still tells him to fuck off --> fuck off
NeoGAF user doesn't particularly care whether the ACA gets repealed or not --> fuck off
Anything short of just saying "fuck off" prompts a "fuck off."
I think this is an emergent property of the modern political context, where it feels like the stakes are so high, you have to do absolutely everything you can to achieve the right result. Global warming, healthcare, anti-intellectualism, the military industrial complex, the school to prison-pipeline. These are all major issues that have real impacts. As a result, people may feel they can't afford to make a mistake, and one of the easiest ways to make a mistake in the game of politics, is to put trust in your opposition.
I do think in this particular case, it is a bit over the top, but I understand where the sentiment comes from.
It is worth pointing out as an overreaction, but it is also understandable to have that reaction.