Clarification. What I meant was, did I sin for having these beliefs? When I learned that these beliefs were wrong, I immediately stopped having these false beliefs.
No. While ignorance is not an excuse for sin, one cannot commit a mortal sin unless one does so willingly and knowingly. That being said, confession of any sins and shortcomings is recommended, along with the required confession of mortal sins. Confession gives us graces to resist sin, and heals us from the wounds of sins.
Yes I would say that alcholics and porn addicts are definitely slaves to sin. Any kind of addiction is characterized by a loss of control or failure of willpower. When one has urges that are out of control, and are leading the person around by the nose ring, ,they have become a slave. This can happen with gambling, sex, video games, etc.
Anything in our lives that competes with Almighty God for first place can make us a slave to it. St. Paul writes some important principles for identifying these things:
1 Cor 6:12-13
All things are lawful for me," but I will not be dominated by anything.
Nothing on earth should get us in it’s power.
1 Cor 6:20
20 For you were bought with a price; therefore glorify God in your body.
Anything that does not glorify God.
1 Cor 8:8-9
9 But take care that this liberty of yours does not somehow become a stumbling block to the weak.
We should not participate in any activity that may lead others astray.
1 Cor 10:13
13 No testing has overtaken you that is not common to everyone. God is faithful, and he will not let you be tested beyond your strength, but with the testing he will also provide the way out so that you may be able to endure it.
There is ALWAYS a way out of temptation.
1 Cor 10:23-24
“All things are lawful,” but not all things are beneficial. “All things are lawful,” but not all things build up. 24 Do not seek your own advantage, but that of the other.
Is it beneficial? Does it build up?
1 Cor 10:31-11:1
So, whether you eat or drink, or whatever you do, do everything for the glory of God. … just as I try to please everyone in everything I do, not seeking my own advantage, but that of many, so that they may be saved.
The glory of God and the salvation of souls should be our primary focus. Anyone who is enslaved to sin will not be in a position to keep these primary.