This is an important post and I appreciate you taking the time to elaborate.
I too am a convert. My road was Mormon, Anglican, Presbyterian, and non denom until I finally found the Truth. I “Lived” in sin with several women. I sinned myself constantly. But here is the thing. I knew it was against ANY real Christ centered teaching of any denomination. Because of logic. People got married in Churches. People got married period! This told me something, this told me marriage is for something. Not only that but many people religious or not were not living as they knew was correct. Pastors were doing bad things, so were their families. I never assumed that if a pastor divorced his wife, left his kids and hooked up with the choir director that it was not sinful. In fact as someone who also had some calvinistic influences I recognized that everyone was sinful. And not only sinful but disgustingly so. It made perfect sense for me to see the ministers kids doing drugs and shacking up. Why? Because “hey brother, we are all sinners” And “I am the biggest sinner” (As if that meant some brownie points in heaven for some sort of false humility and a life of debauchery.

) But here is the thing, I No matter what I did, drinking, drugs, sex, ABC, partying, masturbating, porn, illicit sex acts…etc. I never ever would have made the argument that they were holy, or that my Church taught them just because I saw other people in the Church even pastors doing the same thing.
Of course it was sinful. But what could be expected of me? I was a sinful person, in need of a savior. So of course I did these things. But could anyone, any church, I knew of make the case for these things NOT being sinful? No. But that is the thing. You probably could make the case for mitigated responsibility if I just did not believe or care enough to think about these things. But I did. I thought about them theologically. I thought about them because I was a member of a faith.
I think you could also say the same thing about Catholics. Look, I have confessed masturbation, and ABC to priests who have told me that the Church does not condemn these things. That it is not sinful and perhaps that I could not even help it. I have had a priest tell me to use ABC for the betterment of my marriage. Now does this mean that the Church teaches these things are moral and non sinful? No. It means that the priest was wrong. Does every person (Catholic) who went to this priest have no culpability for the sin if they are given bad council by the priest? Invincible ignorance does not work that way. Nor does God’s saving grace. Just like I knew that murdering someone was sinful when I was a protestant no matter what the way to redeem was. I knew that the priests were wrong. It would be one thing to claim," I was raised by godless hippies that taught me to masturbate from 5 years old on and I never heard of God or marriage on our commune."
But to be raised in a Christian Church and in a Christian society, one that puts people in jail for public masturbation, and of course the Church encourages you to read the Bible… Well, there really is not an argument. The argument is that it was sinful, but it did not matter because I was weak and Jesus has forgiven me and saved me… Because they do not understand Mortal and Venial sin, there is no answer how to rectify one’s sinful nature post baptism. So that is why confession is such an amazing sacrament and why I often lament the idea that somehow a protestant has to make it to heaven without this gift, and without the Eucharist.
Most every sin I have ever committed or will commit or am committing I know is wrong. I do not try to defend it and I may not know exactly WHY it is wrong, but I know.
What I see a lot of on these forums is a teaching or a sin that people struggle with and they cannot admit they are wrong. They claim that no one told them, or that their circumstance is different. Honestly that is the biggest satanic lie around. Because that lie and pride and mindset and shirking of responsibility keeps the confessionals empty. Just like the devil wants. We sit here and argue about culpability and mortal vs venial and ignorance et al. Wishing to be correct and maybe applying a little of our own arrogance, pride, and guilt into the conversation when really what is ALWAYS needed is that the person go to confession. They should be getting the advice and forgiveness from the priest, not the internet. And the priest should be faithful and knowledgeable about the faith!
Ignore the fact that the OP already confessed this. And just read the title of the thread. The answer is " talk to your confessor"
Always. I do not want to be part of a judgement of others by in any way leading them down my own personal theology and away from the welcoming arms of the Father in the Prodigal son in the confessional.
I take issue with what you said about the Bible. It cannot be twisted to support any act. You cannot make a case for homosexual pedophillia or other things. And you cannot make a case for masturbation. I dare you to try!