This reminds me of a guy I went to college with. We weren't "friends" per se, but we had several classes together and were on friendly terms--we'd frequently make small talk before class began.
One day, one of my professors asked me a few questions about veg*nism during classtime. Mainly he just wanted to know what sort of things I personally would and would not eat. I didn't like being called out that way, but I gave some simple answers with no big AR speeches or anything of that nature.
This one particular guy, however, got very agitated. "I think everyone should eat whatever they want, and everybody else should just shut up about it," he interrupted the teacher.
After that, there was a sea change in his behavior toward me. He stopped speaking to me before class, and the only ackowledgement he would give my presence was the occasional dirty look. It was just amazing...one of the most extreme reactions I've had.
slops, gloops, and gruels.