There's plenty of errors in their theology on this but I'll say that the fact Jesus in his own teachings and that of his followers thereafter saw a distinction between matters of the spiritual and the temporal means they're in error. The laws of the land protecting individuals are not tests of faith except where such laws force to you to believe or espouse otherwise. Marriage in this regard is civil marriage and not spiritual marriage (marriage affirmed by God or that of church elders). The fact they conflate the civil (temporal) with the spiritual amuses me to no end because it shows the mental gymnastics they'll go through to assert the Kingdom is a literal domain on Earth despite the canon and non-canon sources for what Jesus said on this (i.e. the Kingdom isn't the temporal/material). So, I think there will come a reckoning in the church if/when followers start to read their own Bibles and not listen to their pastors (the spirit of discernment is not exclusive to church elders). I just wish to live to see that day as much amusement will be had when it all falls apart.
Theologically, I agree, but I'm not sure what would cause the followers to actually question current teachings. Usually, followers of a movement don't question the path taken until they lose confidence for some reason (like Democrats recently discovered). When it comes to religion, such losses of confidence seem to usually be on the personal level, so a large scale reckoning seems unlikely.
