I have never once been accosted by or have accosted vegans on their dietary preference

Congratulations, I wasn't talking about you specifically because I don't know you specifically.

Your imagination is perpetuating the myth of the vast majority of people caring about an individual's dietary preferences.

No, I'm reversing the myth OP was perpetuating that vegans talk about being vegans constantly. There is no myth that "the vast majority of people care about an individual's dietary preferences." I'm using hyperbole to demonstrate what would happen if in a hypothetical situation where a vegan didn't mention that they were vegan to explain why they weren't eating meat. The hyperbole comes from the non-vegans not understanding why someone would not eat meat, forcing the vegan to announce themselves. Suddenly, the vegan, despite all their efforts not to, has perpetuated the myth that vegans constantly talk about vegans. In the hyperbolic situation - being used to demonstrate the inanity of the vegans-always-talk-about-being-vegans myth - the non-vegans represent people who perpetrate that myth.

Thankfully, that's not you. Sorry if you felt attacked.