I try to express this in various ways, but don't think I've quite managed to do it. Trump is a problem, but Trump is not the problem. Sure the Trump agenda might, around the edges, be a bit worse in some ways, but policy wise would Little Marco's agenda be any worse? It's Mitch's agenda. It's Ryan's agenda. Rubio pretends to care about the DREAMers, but he's totally cool with cutting immigration otherwise.
It isn't about Rubio. He's just an example. The problem is a deeply horrible Republican party, from which we can count on no saviors, and a feckless opposition that is blowing it*, as they did during the election, by making it about Trump instead of about Republicans.
*I predict Dems will do well in November (well enough to take the House? Don't know!) and then...?