Perhaps he recognises the futility of the UK's vote? 72 proposals and 72 dismissals.
Its like some parliamentarians not showing up to vote in the HoC. You only get two options, if you disagree with both what would be the point in throwing your weight into the ring?
I would rather the expenses saved in such an instance.
Surely to debate and get people to your way of thinking with rational and logical statements?
Turning up for a vote and calling people names and using it as a platform to further your own ends of the UK leaving is never going to get other people to change their votes is it? In fact anybody undecided would probably vote the opposite to him especially if he had just insulted you.