Did you ever consider that he wouldn't do it 'just for fun' if he cared what you thought and do you think that he would do it to people that he didn't consider to be a 'pompous arsehole'?

If you don't care for a person's opinions, it is best to ignore them.

If you do care, you respond with a sense of common and civil politeness, even if you think they're pompous; and do not pretend for a moment that just that because a person appears to be dignified, stately and respectful that they are in fact just being ostentatious - the behaviour could be genuine and indeed it is far preferable to assume that it is.

It is possible to express one's opinion fully without engaging in the sort of comments and behaviour better suited to those who lack a good response.

Engaging in abuse is for "fun" is an example of arsehole behaviour, regardless of the context or whether or not you even like the person or not. It is respecting the person as a human with the right to respect and dignity equal to your own.

You really do need to get over yourself and find a more productive use of your time.

I will let my achievements and the respect of my many and dear peers be the judge on whether I use my time effectively and productively.

I suggest you consider what you are doing with your time.

It may help you become a better person.