There are a number of reasons this happens.
Biggest of all is that NHL officiating is literally designed to be corrupt and incompetent. Game management is prioritized over calling a fair game and protecting the players, in order to manufacture parity. And each rule in the rulebook is applied to a different extent. We also don't dive, and anybody that is good at drawing penalties is immediately targeted by the media and they become the exact opposite, where anybody can abuse them in any way without consequence. Because of the culture in the NHL, hired refs tend to either already have pre-existing biases against Toronto, or are so scared of being perceived as biased in favour of Toronto in a big spotlight that they end up biased against Toronto. We're also not a market that needs to win to feed the NHL money, and we're not one of the areas that's trying to be grown, so we're not ever one of those teams that gets targeted to be propped up.
And nothing can ever be done about this undeniably broken system, because the NHL executives and owners don't care and just want their money, the media doesn't see the fight as worth it as it doesn't drive viewership and just questions the integrity of the product they paid a lot for, and anybody else that calls it out in the slightest way gets massively fined and shut down, or labeled a whiner making excuses.