[Dawn531]

I’m only a rightwinger that went to Exeter and Harvard so what do I know.

Well, I'm a rightwinger who went to a local university, but I know you should have used "who" instead of "that" in your sentence.

Sorry, just kidding, couldn't resist.

[RebelViking]

“should have used “who” instead of “that” in your sentence”

Using the word “that” as a relative pronoun is, as far as I know, perfectly acceptable when writing about one’s self.