Do you believe an employer should be able to fire someone for what they do outside of work. I say no. The boss has no business what you do when work is finished. If what you do does not interfere with work its not the bosses business.
when what you do does interfere with work you should be fired. Such as in Ireland if you have a child sex offence you cannot work with children. However unless your crime affects work I believe you should not be fired. Its also illegal in many places to be fired for a criminal offence.