The thanking part will generally get a downvote: it's polite in a normal conversation, but it's just clutter. An upvote is sufficient. The real issue (imo) is this:

> Ah, yeah, I'd forgot about those areas having strong right-wing links.

This is taken to mean that, if there is an idea or conclusion that 'right-wing' people agree with, it is therefore wrong. And you not only think that, but you're thanking someone for reminding you to not actually look at the information objectively, but dismiss it out of hand because the _wrong people_ think it.

It's really revolting behavior.