AITA for using my cousins religious beliefs to defend my SO?

For context: I (20F) and my boyfriend (18M) were recently invited to a grill out to celebrate the holidays. My family is also very religious and myself and my boyfriend are apart of the LGBTQ+ community. My boyfriend is a trans male and we both go to extra measures to make him feel more masculine until we can afford the surgery’s.

The invite to the grill out went over normal expectations time food etc. I would also like to mention that this is more about extended family than anyone else. I have an older cousin who we will call Clayton. Clayton and his wife have three kids and we’re just married this year.

During one of the normal banters of our family picking on each other about who inherited what genes through which family members, Clayton decided to bring up religion knowing full well about me and my bf. While brining this up he preaches that the Christian god is the true god and no sin is greater than another except for blasphemy and that no person should pass judgement onto another person. Now normally this a fairly common occurrence he normally was fairly open about his beliefs not in the shove it down your throat way but he would also ask questions as if he wanted to better understand being trans. My boyfriend during these occurrences believed it to be genuine and was bonding with my cousin very well, for context my boyfriends family is extremely religious and everyone save for his brother and a few distant relatives have cut him out.

The conversation was calm and normal up until Clayton brought up my BF for rly being a girl and continuing to call him a girl and say that he was wrong, saying that what he was was a mockery of his god, I told him that he had just been preaching about no person passing judgment. Trying to defuse the situation trying to remind him to practice what he preaches. However the comments kept rolling in “Yet, instead of decimating His creation as your relationship has, I've brought new life into the world.” Keeping in mind he had all three children out of wedlock. I said that if no sin were greater than another then his sin was equal to mine. He then called us both ignorant and stated “He's not going to be OK with you loving a woman, no matter how far into the world and years we go.” So in the utter rage that had consumed me at the amount of disrespect and hurt. I stated “You know that having children out of wedlock lock is very disrespectful in gods eyes”

Clayton completely lost it and said that I was a disgrace that neither I were welcome at his home or with his family, stating that I “threatened” his children. When all I really did was turn the table so he could see it from my perspective. AITA? Did I over step? Did I come off as threatening or did he?