I think the thing is that 4chan is mostly anti-establishment. Obama promised CHANGE (anti-lobbying, supporting lower classes) and at the same time bringing troo

I think the thing is that 4chan is mostly anti-establishment. Obama promised CHANGE (anti-lobbying, supporting lower classes) and at the same time bringing troops home, something that would also appeal to conservatives. Plus he was fairly open and media-savy which provided a lot of material for memes, e.g. the situation room photo when they got osama. When he failed to achieve his promises - certainly due to republican blockades to some extent - he was seen as a disappointment and trump became THE spanner in the works of washington. Another important polarizing issue is the vocal social justice movement in colleges, on tumblr, in the media etc. Since it is seen as infringing on free speech where it matters to 4chan (games, porn, unfiltered non-PC conversation, trolling) they are seen as a threat. If the left does not radically defend free speech, even when it is unpleasant or could be considered as hateful while the right promises small government and has crazy libertarian subcurrents then this is actually more value-aligned, at least on the surface, with 4chan interests. I don't think a timeline where bernie had been the 4chan favorite would be inconceivable.