I think, given the context of your other thread, you've written something quite misleading here.
It reads like you're blaming him for being gay, and blaming him for the associated knock-on effects this is having on your family.
Your son is asking for support. And, by the sounds of it, not getting it from either you or his father.
He is 16 and gay with, by the sounds of it, a homophobic parent (possibly two). He will feel desperately lonely and at odds with pretty much everyone around him. His social circle will feel tiny and he will be watching his straight friends do things that he feels unable to do.
His desire to go to Pride isn't driven by a want to roll around in kink or dance in his pants on a float. He wanted to go because he thought he wanted to be in an environment with other people like himself, for once in his life.
What you think of Pride is largely irrelevant. What a bunch of strangers on a forum think of Pride is similarly not the point. He wanted to go. Teenagers don't always make the most nuanced choices. But they have to go through stuff in order to come to their own conclusions about things.
He may or may not make his own decision about how relevant Pride is to him at some point in the future. But right now he's trying different things to find his 'tribe'. And you just shut him down. You didn't even let him have a chance. You didn't even let him try. You've reinforced the message that society will reject him, that gay culture is freakish, and something to be afraid of.
Your poor son.