The Catholic Church is just an easy target for them because it stands out and is one of the largest congregations. They hope that they can break the Catholic Church and use it as an example to intimidate everyone else.
A stupid, stupid strategy, IMO, but we’ll see. The RCC is a large enough “congregation” to make or break a candidate. Now, there are plenty of Catholics who use birth control. There are plenty more who don’t agree with the doctrine on it. But they will ALL see this as an attack on the church, an attempt to turn the clock back to when the prejudice, ignorance, and hatred of the church were not even concealed. I think people see this as more of the same old marginalization. He’ll lose 90-10, and if you add Baptists to Catholics, you’re talking like 100 million citizens. To top it off, he’s put the USCCB in a corner. They CAN’T accede to this without becoming like the Catholics in Germany-collaborateurs without any credibility or power.