I'm saying this all in a very friendly manner, FYI
1. Without getting into the theological differences, Roman Catholicism is just another form of Christianity like any other. At it's core it's really just about having Faith in the teachings of Jesus*. Also, a lot of Catholics
do make their own interpretations.
2. As I said in my other post Catholicism is more than a religion, it is also a culture, and it's a culture so old that it directly descends from the political institutions of the Roman Empire. That means a lot to some people. It's a source of community. Also, a lot of people simply like the liturgy and ritual of Catholicism.
3. This is a question of debate, but from a practical matter all of those "rules" are cultural baggage that many (if not most) Catholics ignore. It's really not an issue except for the deeply conservative.
4. Then you should apply this to all Christians in general and not just Catholics. However, you should note that Jesus actually says nothing whatsoever about marriage, and theologically it's not really an issue. Again, homophobia within Christianity is cultural baggage more than theological baggage. Abortion is a more complicated matter because Catholicism teaches that all life is sacred. Still, on a practical matter this is a personal issue for most people.
*If you're interested the principal difference between Catholicism and Protestantism is the concept of
sola fide. Protestants teach that the key to salvation is by Faith alone, but in Catholicism (including Roman, Greek and Middle Eastern churches) the key to salvation is Faith and works.