They're angry at Trump because of a lot of reasons. The rank and file are angry for him slashing benefits for people who're only on them because they're too lazy to work, while the ones at the top are angry for him slashing useless programs that ultimately put money in their pockets, stopping their plans to use illegals as a new voter base, and redistricting to counter the out of control gerrymandering the Dems did. Okay, sure, Republicans do it too, but not NEARLY to the extent that the Dems have. I mean, I'm pretty sure there's a state with 40% Republican voters in it who don't have ANY representation thanks to Democrat gerrymandering.