I looked at jrcii's account and see what you describe: jrcii was feeling his oats after the elections and took a Trumpic victory lap by posting a pretty snarky comment on YC. In that comment jrcii disses:
climate warning, "Silicon Valley people, LA people, NYC people, city people, liv[ing] in a bubble formed by the urban politics around you and reinforced by liberal college professors, the liberal students they create, and the liberal mass media. This is simply not reality for vast swaths of the country."
https://news.ycombinator.com/item?id=12917083
OK, so he does this once, just once. There's no pattern of misbehavior. He didn't threaten anyone (no "Second Amendment People" comin'!). For all we know he's the last conservative in SF and needs to blow off steam.
YC is a great forum. I think it harsh for a techie to be banned for a single scattergun comment especially after a heated election. I would think a caution would be better at this juncture, or even some ribbing: "OK, we hear you celebrating! Your guy won this time. But soon we'll find out whether he can ride the horse!" or such.