It is not me that determines this. It is the teachings of Christianity and the inspired word of God, the Bible that does.There are legitimate differences of opinion on what the bible says about homosexuality, after all it's been translated, and mistranslated for over a thousand years now, and in the case of Leviticus, the original Hebrew does not support the anti-gay translations of the book.
So yes, a person can be both gay and Christian, you don't get to dictate that they can't.
There is another verse that states everyone did that which was right in their own eyes. They went against the teachings of the inspired word of God and were judged.