Why do homosexuals try to justify their sins with seafood verses?

Many are attempting to show you that you cannot pick and choose which Leviticus passages you want to enforce. You either abide by the entire thing, or you do not. But we are no longer under the law through the sacrifice of Christ. Those who believe will be saved, including homosexuals who believe (John 3:16-18). Romans 2:1 however states that those who judge others by the law (Leviticus) are really condemning themselves.