If you are an employee and a fellow employee tried to enforce an opinion that had no relevance to the job that you were doing, after you have asked them to stop, then they would be bullying you. That is a gross misconduct matter, that if proved may lead to dismissal.
You may seek advice on this issue from your union, but the grievance should be lodged with the appropriate channels of your management structure. If your management structure ignore your grievance, then there are legal avenues that you may pursue.
No colleague has the right to tell you what to eat, or which religion to follow. They also have no right to lecture you about your terms and conditions and why you should change them, if you are feeling in any way, under pressure to defend yourself.