I don't get it either. They focus on certain sins and ignore others. Many conservatives are mad at the Pope because he is talking about poverty and social justice. That's something Jesus actually talked a lot about. If the sin isn't about sex, they don't seem interested. Conservative Christians love to talk about sex.
If Christians keep saying that some laws in Leviticus don't apply today because of the new covenant in the New Testament, then why do they still focus so much on homosexuality?
I have noticed as well.
Maybe aside from religion...the act is unnatural
Because more than 99% of Christians are hypocrits.
The Old Testament is a record between the God of creation and His chosen people.
When Christ came, he brought a new reality, not a new morality---God reestablished a relation with all of humanity, Jews and Gentiles alike.
Some laws were changed, some remained the same. On the one hand, the 10 commandments are still around, but marriage was made a sacrament (a way for God to share supernatural grace) so some of the "rules" changed.
Nothing unreasonable here, but of course various people will accuse me of confirmation bias---which of course has no bearing on whether my answer is right or wrong.