imho, if a person decides to join a particular church, it only matters if they are doing it with eyes wide open.
Jim Whitney (aka Amazing) decided to rejoin the Catholic church, for very specific purposes. Good enough.
Merry Magdalene decided to join the Islamic belief system, again with a clear intent and awareness. Good enough.
Sometimes I've even imagined myself as a JW again. To be honest, if they would accept me for what I am, then I might not have a big problem with that...which is why I went back the first time.
In that respect, the exclusivity of a religion is perhaps the most telling aspect of its acceptability to thinking people.