They are being exclusive and hurtful by acting like that, and I'd just like to get it out of the way that you shouldn't take them seriously. If it's a problem with a specific group or team, leave. Find a better team. Even if it seems like you're letting them win, you should leave any toxic environment you can. If it's just a problem with general chat, my gaming usually doesn't involve interaction, so I'm not quite sure what to do to stop it, but just remind yourself that your size has nothing to do with your self worth, and that you are allowed to like the things you like, even if others don't approve or understand.