The slap in the face is around the NDP becoming disconnected from the people so much that they thought their clever little ruse of calling a snap election while the opposition was in disarray was a good idea.
Leftists should consider the top down approach doesn't work, assuming a party that's "more left" will automatically win is silly. You need to engage with the people and convince them of policies you want, not try to impose them from above. There is no "silent majority" that wants the same things you do. You aren't going to scam people into accepting your ideas in the same way the NDP tried to scam their way into an easy election win through shenanigans.