He did the right thing.
The participants were lightweight marginal nutters who'd only have ganged up on him and it's hard to see what was to be gained by taking part.
These marginal groups of loonies managed to frustrate parliamentary and democratic process during the last session of the house and during the last three years by working together and I can't see why you'd give them a chance to do it again on tv.

Let's hope their days of collective tantrums against the majority opinion halting progress are over and no one has to go to their yogurt knitting party if they don't want to. The only people who'd watch it without any serious contenders taking part are already set in their opinions.

In the event, the most likely participant to be in power was the block of ice.