Forgive my bluntness but I don't see a theological argument, is Catholicism not a belief? If you believe the Church is wrong does that not by definition negate your belief in the Church's  teachings on its sacraments?

I am genuinely confused, it seems like an paradox to say one is a Catholic as if it is an ethnicity and not a creed. How can you choose to remain Catholic and at the same time reject it? 

Other denominations have very different understanding of ecclesiology, there is in built interpretive authority, while the Catholic church(along with the Orthodox) have as a core belief the idea of unchangeable truth beliefs. It would be like you being a seventh day adventist but rejecting Sabbath worship as wrong, it makes no sense.  

Either it is simply an identity label that you and others refuse to let go due to emotional attachment  or there must be some sufficient theological argument.