I think he is referring to the fact that this is a pretty low-key topic about a website to learn new languages, but your reply involves a very divisive politica

I think he is referring to the fact that this is a pretty low-key topic about a website to learn new languages, but your reply involves a very divisive political topic that you seem heavily invested in. It's almost as if you went up to the counter at an Arby's and started talking about intense political subjects to the person taking your order: it's very out of place.