Because “conservative” isn’t an ideology, it’s a mindset. It’s based on the idea that the in-group is good, not because of what they believe but because of who they are. So because they are good, whatever they want is good. It does not matter if their wants are contradictory or hypocritical or irrational in any way. They define the parameters for what is worth preserving, and then anyone who wants to stop them is part of the out-group and therefore bad. The out-group is not bad because they hold bad positions. The out-group could change their positions, and they would still be bad becauae it is part of their identity.
Conservatives also do not require any justification for their wants, but having a religious justification is like catnip. Because of the conservative mindset, they have no problem picking and choosing the religious beliefs that support what they want while ignoring or attacking the ones that don’t.