Oh, yeah. Super gay. Like, half-in-a-butt gay. Like, smelly balls gay. Like, having too strong an opinion about the décor gay. Like, using the word décor gay. Like, using the word like a lot gay.
Wait? Am I gay?
(takes moment to smell own balls.)
(springs into action with the power of will and heterosexuality.)
Look, if Jon likes it up the duff, more power to him. Whatever makes him happy. I say this because if you're asking me about Jon, it means you're not asking him. Give him the chance to be honest, and then make him feel like it's okay. A good way to make him feel that way is to have sex with his asshole.
Short Answer: If you're curious, based on Jon's lack of copulation with females and/or interest in watching his male friends eat fried chicken, he's probably gay and you probably know it.