The man was right and wrong.
Yes, he's right that it's unfair that some people have wealth they haven't earned and sometimes aren't taxed at the same rate. If he'd have stuck to that point, I would be agreeing with him.
In the other hand, he was wrong about Labour's lying - and that seemed to be his main point. An income of over £80k does put somebody in the top 5% of earners, so he was wrong to accuse Burgon of lying.
He was also spectacularly wrong to claim that he wasn't in the top 50% of earners. He would even be in the the top 50% of everybody, including those with unearned wealth. Therefore, he was wrong with the main point of his shouty claim.