A major thing, at least on HF, is mob mentality. Its the "cool" thing to do is trash and harass Leaf fans. You can see it in the "like" train on all the posts by the usual offenders. Then it feeds into itself where if enough people say one thing, everyone else starts to believe it.
When we drafted Anton Stralman, a Leafs fan posted a quote from Stralman's coach in Sweden where the coach said Anton reminded him of Lidstrom. A few trolls starting linking to this post saying that Leaf fans thought Stralman=Lidstrom, and it spread around the boards quickly. For the next two years it was brought up in every Leaf debate as an example of how Leaf fans over value their players. That's the big issue with trying to get around the anti-Leaf sentiment on the main boards, its so hard to fight stupidity mixed with ignorance.