It's less that they can compromise and more that the only policy that they care about is policy that hurts minorities. They'd happily jump on a grenade or march into an oven so long as they can take a liberal and an immigrant with them.
On the other hand, look at how much effort it's taken for the fascists to get power again. The groundwork for the current administration was started under Reagan and solidified under Bush Jr. They had to take every branch of the government by force to get to where they are because there just aren't enough of their supporters to actually get them into office without bending the rules until they break.
Because that would be "protesting the wrong way." The left is obsessed with decorum, and most people seem to think that if we get enough people holding signs on street corners, then they'll have to stop the slide into fascism.