The cheese pizza thing is a common joke

Republicans in the US went through a phase of making a lot of cheese pizza jokes back during the (Hillary) Clinton administration. It went so far that a cheese pizza restaurant was the site of a protest. The jokes have gone out of favor these days, largely replaced by Epstein jokes. A "gl" is a very flexible term which could conceivably be applied to anything from a baby lover up to an old man who appreciates "girls" in their 20's. A policy that might work well for you is to stick to referring to people the same way they describe themselves. If he calls himself a gl then he is, but if he prefers to identify as something else, then that is what you call him. If you want to you could bring up the term "girl lover" and ask him how he feels about the term. You could admit to your theory that "everyone is a bit of a gl," which isn't technically true, but it's something that a lot of gls say.