They have encountered there own deforming problems.
One is the fact that they have generally adopted the Biblically-condemned Onanism of contraception as morally justified and even desirable.
Another is the crass commercialization of Christianity through the "name-it-and-claim-it" school of simony.
Another is the unbiblical idea that the demonic "speaking in tongues" such that no one understands what you are saying is analogous to the Biblical speaking in tongues of the Apostles wherein everyone understands what you say.
Another is the anti-Christian Arian heresy known as Oneness Pentecostalism.
Another is the LaHaye marketing tool of "secret rapture" and a third coming.
All these are of very recent provenance.
Yeah, theologically and morally, there are problems, but that doesn't seem to be stopping their growth in numbers.