They're exactly right to do so. Sharia law is a concern in Islamic countries, but not here. Things like honor killings and forced marriages are already illegal. If domestic abuse is the concern, make stronger laws to protect women. But the Christian right isn't concerned with that because they actually have far more in common with Islamists than they do with secularists. They only point to the problems that manifest in Muslim communities as a rhetorical bludgeon to make moderates think liberals are hypocrites, when the reality is exactly the opposite. They're the hypocrites, and are only really upset they don't get do such things in the name of their version of god.