You can't say you hate something if you've never tried it. Why doesn't this apply to sucking dick? I say that if you suck dick once and decide you don't like it that is more straight than never trying dick because that means deep down you might have a hankering for dick that you don't know about because you have never tried dick
The skydiving thing was meant as a metaphor. I couldn't think of a lower stakes example in the moment to demonstrate my reasoning that "don't knock it before you try it" is nonsense. It's not to say that being attracted to the same sex is bad, it's just that if you don't feel attracted to them, you don't need to try it to actually prove the feelings that you already feel. If you feel attraction to someone, you should absolutely convey those feelings to the other person! But you don't have to prove it to anyone