I'm sure there is a point being made here about the Mormon church, but I just have to say if this is the argument being made, it flies in the face of common sense and probably undermines the message it's trying to send.

First of all, "code switching" is a totally normal linguistic thing that people do when they're in more than one social circle. Do you greet your kid, your best friend, your lover, and your father the same way? There is no reason why your speech patterns have to be consistent no matter who you're talking to; we all do this naturally without even thinking about it.

More broadly though, I find the idea of "authenticity" to be more often than not an excuse for people to not bother learning the norms of the group they are in. If you come to work and spend all your time "hanging out" like your coworkers are your buddies, you're going to have a bad time. Be a good worker at work, be a good friend to your friends, etc. If you don't like what's expected of you or it doesn't align with your principles, then by all means reevaluate whether you want to be part of that group.