If you want to fight Trumpism and the alt-right, work for social cohesion. Trump tapped into Americans' yearning for social cohesion, the functional communities so many older people remember.
Multiculturalism destroys community cohesion. Real people feel the real loss of social support. By all measures, American communities are not supporting their members as they once did.
Maybe we need to spend some time thinking about what we are protesting about, not just the protest methods. As a lifelong feminist, I did not participate in the Women's March. I read the manifesto, and it was a women-led march for multiculturalism. The concerns of older white women were not mentioned -- imagine a manifesto that does not mention preserving Social Security and Medicare for older American women!
Since I'm a feminist, not a multiculturalist, I did not march. I don't respect cultures that don't respect women.
I don't know the answers for how people fight for their rights while not destroying the community they want to be a full part of. All I can say these days is that I feel politically homeless. Pushed away from the left, but certainly not a member of the right.