I don't think he did. It doesn't matter whether you believe Hitler was right or that Dipsy is the best teletubby, I believe everyone is entitled to their behaviour and beliefs during their time off work without any professional consequences to it. If there are legal consequences from something like harassement, then report to the correct authorities.

No offence but it's it's people like you that make me glad I live in a country where employers are harshly punished for taking any actions against you based on your non-work related activities.