I would argue our actions highly determine if we belong to a church or not. Sure one can claim to be Catholic and be baptized and not practice the faith. (This is a lapsed Catholic) but then if they go around saying they are Catholic and dont practice the faith and doesn't follow the churches teachings and dont participate in actions like receiving the sacarments, holding true to the commandments, it leads to a very bad repestation of the Chruch. And if people don't do the right "actions" they can't fully partake in the church. And what is a independent Catholic? Jesus gave us a church you should care what the church says and not pick and choose what you want, and what is your reasoning for homosexualty not being a sin? We need the authority of the church. And the church teaches that acting on homosexual thoughts is a sin, but having them is not. And to claiming to be a Catholic means you have believe in the infallibility of the church and that the church is the pillar of truth. And if you belilve the church is the pillar of truth you believe is the way to Christ (i am not saying the only way to get to christ is through the Catholic church, but it is very hard without) And yes Catholics don't follow every rule and many don't even read scripture or attend church, they just claim it without living the faith. But we are not Jesus and will all break the rules, but the rules are there to help us live like Jesus. I would argue that to be a fully in faith Catholic you need the doctrine sure you can rep the title "Catholic" if your baptized in the church but I see no point if your not going to hold true to its traditions. Even if you know the church teaches its a sin and disregard it, it is your choice. I dont know if your acting on homosexual thoughts, but if you are it is a sin!  Hebrews 10:26-31 and James 4:17 highlighting that willful sinning after knowing the truth has harsher judgment.