With notable exceptions, wrestling in the United States is more popular in rural areas. Rural areas are overwhelmingly conservative politically. 85% of conservatives (according to Pew Research) identify as Christian. Ergo, wrestling here seems to have a lot of Christians participating.
It could just be that a few high profile wrestlers are very vocal about their Christianity in interviews and on social media, but my guess is that a high percentage of wrestlers in the United States identify as Christian.
I'd be pleased as punch if people kept their religious beliefs to themselves, but I'm not going to hold my breath on that.