Who is “they?”
Comes down to terms of employment. Employers have considerable latitude in setting working conditions, up to the point that they become unreasonable or violate some law. Without doxxing yourself, you can’t say more. But in practical terms, if your coworkers are all mask wearers and you stand alone, it’s going to be tough. There’s always the health argument: prolonged mask wearing is inherently unhealthy, but gaining a sympathetic hearing from anyone in a liberal environment is unlikely. Ultimately, you will need to determine whether this is the particular hill you want to die on, or whether you’re better served by living to fight another day. While you’re employed, you can attempt to influence opinions and subvert the status quo. I wish you wisdom and a modicum of luck. Remember: there is safety in numbers. There is no safety in being a single target.