A few observations:
There are simply more left-wingers on this site (and in the whole country based on vote count) which tends to put those with right-wing views at a disadvantage - "down voted to hell" wouldn't happen if there were more people that shared the opinion being down voted. Right-wingers stay here and complain about hostility because they know that they still have a bigger audience than any site that might be more supportive of their views. The down voting probably feeds into a persecution complex which reinforces beliefs as well (so it becomes almost a badge of honour i.e "those libtard sucks hated that, I must be on the right track)
Trump supporters basically outright refuse to have good-faith discussions about their candidate, instead dismissing anyone on the left as a cuck or libtard or whatever - and banning dissenting views from t_d while ghettoizing open discussion over to ask_d.
Trump supporters have firmly decided that the left = Hillary. They have a continued obsession with Hillary (even right now there are a handful of threads on the front page of t_d about her). Hillary lost (even though millions more Americans voted for her than Trump) and the left is moving on while t_d are still using her to deflect scrutiny away from some of the questionable shit that trump is doing.
A complete inability to think critically about their candidate. Just once I'd love to see a response to a criticism of trump go something like "You might have a point but have you read about trumps plan for XX topic? It might change your mind". I've never, ever seen anything like that.
Their political viewpoint is based on hatred of Liberals. I don't hate right-wingers, in fact I understand where they are coming from, I just think that they're wrong. On the right it is pure hatred and disgust for the ideas and principals of left politics. It's hard to be open and welcoming to somebody who literally views you as sub-human.
I created a throwaway to make this post because some Donald supporters seem unbalanced enough to actually make my life difficult if I post this on my main account. Like it or not, Trump supporters, those are the people that you are lumped in with on this site.
I welcome a conversation about any of the above. I feel that I have been fair and not terribly biased against your candidate, so consider that before you click the down vote arrow.