It comes to something when the only defence of a PM who lied about no rules being broken, and who has instigated an internal investigation to buy time to come up with spin on the question of other breaches is to blame the person who 'ratted on him'.
We are not in a prison drama like Bad Girls, where 'grassing' is the ultimate crime. A PM who makes rules for the country that he doesn't keep, who turns a blind eye when those close to him break them, and who lies and wriggles when he is found out is significantly more serious than the quiz itself.
The quiz is effectively a metaphor for his leadership, and that is why it's so serious.