I agree, but it's not just a vague sense of unease that bothers me. It's actually very real and very concrete.
I am probably in the very far left-wing on this website in many regards, and what I see in a lot of this effusive and reflexive anti-Trumpism, is a lot of dubious and easily rolled-back gains. At climax radical right-wing activity, the GOP can just throw Donald Trump under the bus, and I think this would completely destroy any of the coalitions currently being built up against him, because the agreement on everything else is vague.
A lot of people really and deeply want to believe that the problem is Donald Trump himself, not the entire institution that props him up. I've seen numerous liberals (as opposed to leftists) on the internet openly and effusively embrace John McCain in his fashionable and phony role of maverick, the man who sang "Bomb Iran" to the tune of the Beach Boys. It's bewildering.
Another example is the Women's March. A friend of mine mentioned to a fellow protestor how important it was for her to fight for reproductive rights, and this woman's response was that it wasn't even about that, it's mostly just about Trump's disrespect towards women. And if you go on the movement's website, it's true. It doesn't mention planned parenthood or reproductive rights at all. Some people see it as a virtue, I think it is a strategic error.
Moreover, I think everyone on the broad left clearly understood Donald Trump's "Make America Great Again" as a dogwhistle for bygone years largely characterized by white supremacy and a vision of the ideal normal nuclear family. The real surprising thing is that a lot of the impassioned, patriotic rallying cries against Trump today, by celebrities who describe themselves as patriots who were proud up until yesterday, are exactly the same: "Make America Great Again". It's just that they pine for the great Obama years instead.
There is almost zero mea-culpa about how it was possible that Trump got elected in the first place, and it's become so important to "stop Trump" that criticizing allies is a huge faux-pas. I don't see this building into a healthy strong movement.