I've known people who were just deeply genuinely nice people. Yeah they can go totally authentic and are entirely welcome. Hell they can invite themselves over for dinner to my house and I'll be happy about it.
My authentic self is sharply sarcastic, critical and at times brutal. My coworkers don't want to deal with that - that's a very chaffing personality especially towards the end of a stressful week and it can very genuinely hurt morale. I very much tone myself down, avoid sarcasm as much as I can, carefully massage critical and direct messaging as best I can and generally try to be aware that the people around me have different communication needs.
And I think people do get a taste of the real person under the facade. I know I get that from my coworkers - I have coworkers who are great coworkers but whose friend I have no interest in being because same thing, their "out of work" authentic self I find off-putting even though they are amazing coworkers.
Not even the most conservative white collar place (super super well known big classic old school engineering company) has ever mentioned jack shit when shit was burning to the ground and we were trying to keep things working
Some workplaces:
- penalize black women for having natural hairstyles like locs
- make Sikhs remove turbans
- deny chosen names and pronouns
There are entire swaths of groups who can't be their authentic selves.
What I don't do is bring all of myself to the workplace. Professional relationships are different than intimate relationships and not every part of me is appropriate for both kinds of relationships simultaneously. But every side I show is authentic.