Pronouns in Email Signatures

Hi all, 

I am looking for advice on using pronouns on email signatures. Our organisation has a communications strategy which includes the format of email signatures. 

We have since delivered LGBTQ+ training and the use of pronouns on emails came up. Since then, a couple of staff (we are a very small organisation) have added their pronoun to their email signature. We have since received a query from another member of staff (who did not attend the training), why someone is using this and if there was management approval. This individual who has queried this is a devout Christian and disapproving of this sort of thing (she was extremely judgemental to me when the team were discussing our weddings and I informed the team that I had a humanist wedding).

My query is, is it ok to allow individuals to choose to use their pronouns and not "force" staff who have religious views to do this also? We were just going to allow everyone to decide if they wanted to add their pronouns to email/written communication, rather than have a policy on this.

Thanks in advance.