I think you're right about the need for debate around how identity politics can be better expressed and that is a debate that seems to have been slightly suppressed on the left. I would say two things about why I don't think this is a good reason to support Trump:

1. The situation you describe is fundamentally about freedom of speech vs the right not be be offended. Trump is not an advocate of freedom of speech and doesn't believe in a free press. In my estimation this is much more dangerous than what you describe.

2. This doesn't even register on my scale of the pros and cons of Trump. The Presidency is not about who decides who gets to say what to whom, that is a matter for society at large. As has been described elsewhere in this thread the damage he will do (if he enacts even half of his platform) to immigrant and womens rights, America's standing in the world and free trade will outweigh a hundredfold any small gains you get from a backlash against political correctness.