It's as simple as that.
American culture is garbage and wherever it establishes itself Protestantism grows in lock step because Protestantism always digests and rationalizes whichever portions of the garbage it needs to keep drawing in the wallets.
None of these "good Christian" Protestant churches are ever going to start focusing on what they know will send their members elsewhere no matter how clearly it's evil and a sin. There won't be a series of sermons by any of the "Evangelical Christian" self-appointed "pastors" focused on the fact that contraception is abortion and abortion is murder. All the self-appointed shepherds know their crowds and membership would dwindle to nothing the same way membership in Fundamentalist churches that hung on to preaching against rock n' roll, dancing, and drinking beer, a bit too long dwindled to nothing.
The only real doctrine the vast majority of Protestants outside of the SBC have is, "go along to get along".
R: None of these "good Christian" Protestant churches are ever going to start focusing on what they know will send their members elsewhere no matter how clearly it's evil and a sin.
Talk is cheap and that is part of the problem Evangelical Christians have with the hypocrisy of the RCC and it's members. The RCC talks a great game, but when push comes to shove RC's vote for baby killers and RC apologists attempt to obfuscate the issue by claiming they really are conservative. RC's were one of the key voting blocs that gave us this tyranny from obama and the left. Lets see how RC's vote this time around.
Personally, I think it will be more of the same from RC's. However, long term I see hope because so many Hispanics are hearing The Gospel, being saved and becoming Evangelical Christians.