Reading the game threads of other teams, fans are all always complaining about the refs, especially when their team loses. Not just in hockey, but football, soccer, basketball, and every other sports except baseball, where they blame the umps instead.
I don't think anyone has ever said "wow, the refs are really winning us the game tonight, ignoring all our fouls and calling even imaginary ones on the other team!"
According to the fans from other teams, refs are all biased in favour of the Leafs.
Most of it is just perception: bias is in the eye of the beholder.
Leafs play soft. When you don't fight your way through a check, and make passes long before the opposing player is close, you don't give them the opportunity to foul you.
And, yes, refs miss calls - they are only (sub)human after all.