Self-censorship to prevent grievance being filed by classmate
You are, it appears, being bullied. You will encounter people with strong, even irrational feelings irrelevant to you and your work with some regularity over your career. Engaging is seldom useful. You are not responsible for his demands, and this issue is not one in which it appears you want to involve yourself. In your coming meeting, engage as little as possible with his narrative. Bring all topics back to how you are being made uncomfortable, and how you wish to be left alone.  You are correct in your statement, but don't seek to assert that. Just let this angry individual exit your life without engaging with his angry demands. If he escalates, your department will certainly help you; use that.