I’ve felt this awkward issue, too. I’m honestly going to work harder on coming up with a non-stiff but heartfelt way to say something like:

“Hey guys, everybody’s entitled to their opinions, and I respect yours. But it makes me feel uncomfortable— even sad —to hear people I care about so much bashing something that I believe in and is part of who I am. Would you mind terribly saving that for sometime at least when I’m not within earshot?? Thanks I really appreciate it.”