Yes you have the right to tell your employer to "fuck themselves", but will find that you no longer have a job a millisecond later. When it comes to an employer-employee relationship an "optional" request isn't really optional.

> Can't they be simply told to go fuck themselves and do not stick their nose where it does not belong?

If you live in a country where corporations are subject to the rule of law, sure.

America has "at will employment". Except for certain classes (gender, disability, race, etc.) that are illegal to discriminate against, an employer can fire someone for any reason. Therefore, employees have to go along with what the employer wants in order to keep their job; even if what the employer wants is unreasonable or illegal.

I agree with you with the caveat that it's "only" most of America (it can vary by state and even whether you work for the local government or not).