Philosophical response:

I've mostly dealt with that during the years I lived in Texas, where I often encountered religious zealots.

It tends to be situational... I generally avoid arguing with zealots because they are basically "in their complex" and trying to change that is like wrestling with a fully grown pig... It make ME dirty and it just annoys the pig... and the pig is still a pig.

Usually, I just leave it at "that's very interesting" and then beat a retreat and do my own thing, anyway. Even if they have "legal recourse." I might step a little more lightly, but I'm still likely to keep doing my own thing... while studying ways to undermine that legal recourse... mostly by spreading confusion and ambiguity.

I might try the "I see you're very committed to your beliefs, and I respect that... and I hope you will respect that I am equally committed to mine," approach.

I'm far better at manipulation than brawling... but you've probably figured that out!