Yougotbale there has been a good deal of theological debate about Leviticus. The verses about men not lying with men are actually part of the "Holiness Code" which is a ritual for Israel's priests. Sex between men was used to demonstrate dominance of one group of men over another, particularly in times of war. These verses have nothing to do with loving relationships between people of the same gender - unless you're a fundamentalist who takes them out of context!
The "abomination" mentioned in Leviticus is unlikely to be referring to gay sex between loving partners. The original word is "toevah" which is usually associated with idolatry and so the passage is probably about the Canaanite religious practice of cult prostitution.
My religion doesn't frustrate me, as it is a personal relationship with God through Jesus, it's not defined by other people or organisations. But yes of course I find it frustrating when I see unfair discrimination in churches. I don't think God is going to judge organisations, he is concerned with what is in the heart of the individual.
I believe in freedom of speech and freedom of religion, so yes I think churches/religions that I strongly disagree with should still be allowed to practice. However, I don't think it's right that the Church of England, which is meant to be equally available to everyone, should be able to discriminate. I think they should either include everyone properly, or lose the right to be the state church.
How about you, do you think religious people should take their historical books literally word for word, or read them in context and interpret them as best they can? Do you think religious groups should only exist if everyone in them agrees on everything? Do you think open-minded religious people should give up on meeting with others of similar views, and let the bigots take over all the organised groups?