If a man is more comfortable identifying as a women and vice versa,
it's their business.
What I may think is of no concern to anyone else.

No one cares what you think. They do care about what you do.

You have every right to think all kinds of anti-Catholic thoughts, for example. You can ruminate over and over again about how Protestantism is the one true faith, and how those "damnable Papists" are destroying the country.

But you're not allowed to engage in certain actions based on those beliefs. You can't refuse to hire Catholics (with some exceptions not relevant here). You can't go up to Catholic co-workers and berate them for their religious beliefs. You can't insult Catholic customers in your place of business because they're Catholic. Etc.

If you work at a big company, they're going to tell you that you shouldn't do certain things to your co-workers that might make them unhappy at work. One of those things will be (as noted above) that you shouldn't make them feel bad for having religious beliefs that are different than yours. Another will be that you shouldn't make them feel bad by using pronouns that don't line up with how they want to be referred to.

Albaby