Trump got to where he is because of Twitter. Hes a product of the social media age. Gen Z respond to him because he understands internet culture, especially the vile parts like how to dominate a conversation by trolling etc - nowadays if you say something controversial, dont put out a PR apology, that hasn't worked since the 90s - instead, double down on it and throw an insult back. I think thats why (some) GenZ respond to him. None of this is a good thing btw.

TL:DR Brainrot