There is a reason why older people with medical problems fear medical change and why 18 year old college students without health problems do not.
I don't think the progressives that are talking about healthcare reform are doing it because they don't want to have to pay the premiums, I think it's that they actually fear the cost of healthcare, which due to the lack of increasing wages, and the increase in cost of getting into the "professional" classes, leads many to see themselves as screwed if anything goes wrong with them.
To your point about sympathizing with Trump voters dislike of the democratic party, I could see them saying they hate or are frustrated by the democrats, but not just being like "Oh, yeah, let's be best buds, Trump Voter." They want to constructively criticize, but those in power can't see their missteps and refuse to listen to those who are trying to warn them. Are there certain "lefty" circles that sorta back him, but that occurs on each side of the isle, with the Lincoln Project being an example. To be clear, the lefties I've seen that have gotten buddy buddy with the idea of another Trump tenure have been denounced.
Quality does matter with healthcare. Long wait times are not something anyone wants to deal with, at the same time though, much of the concept of long wait times has come up due to under-funding, as well as anecdotal evidence put out by insurance providers in America. Older people with Medical Problems generally have some type of Medicare though, so it's sort of silly to complain about socialized medicine being such a drag on the system. It's just those benefiting from the current status quo not wanting change at all. Which is normal, but you can't pretend it's not a bit selfish on those who are on such a system then turning around and saying no one under me should experience the benefits.
Regardless, healthcare in America needs to be improved, both on the cost to the patient, the cost to those interested in getting the skills for being in the medical field, and the health outcomes.The only way to avoid wait times is to have more doctors, which gets hard when they can't afford the price of admission.