This is just wrong:
"You haven't established that gay sex is a sin, except that you holy book says so."
How can we establish that anything is a sin via secular sources?
Great question! One of the reasons why I don't accept the concept any longer.
Also, please stop judging me without knowledge. I went to high school on the border of Greenwich Village and have gay friends and family.
"I have a black friend" does not impress me. I didnt judge you, I judged what you said. You believe things that are simply unfounded about my community.
The life is harmful and you're in some pain
That's true - the pain I'm in is being told hurtful things that aren't true about myself and my LGBTQ brothers and sisters by people like you.
--unless you suppress your conscience and what is revealed to you about God, who loves us both. The Bible explains how you and I both either allow God in our knowledge and hearts or suppress Him.
Your attempted guilt trip is noted, and won't work.