I haven't read this entire thread, so pardon me if this has been expressed already...
I think there's a big difference between criticism and negativity - and I think things might improve somewhat if people could learn the difference and try to temper their posts accordingly.
We all can get frustrated and disappointed with a loss or if the team or certain players are playing poorly. But sometimes we "shoot from the hip" and it comes across as negativity, which in turn sets off other people who are trying to be more positive or balanced.
Example - the same feeling/thought expressed different ways:
Criticism - "If this team keeps playing with this lack of passion/finish/discipline we're one and done!"
Negativism: "This team is done!!"
Now the first statement isn't as inflammatory as the 2nd. Even if you're generally optimistic about the team, you may very well agree. Sure, IF they continue to play poorly, they'll fare poorly. But the absolutist negativism of the 2nd statement gets some people's hackles up.
I may feel the team can turn it around, but at least I'd be prone to agree with the criticism of the 1st statement, which at least doesn't get everyone's hackles up, and may even open up a reasonable conversation: "So, hey, why are they playing badly right now?" etc., which is more likely to result in a discussion of hockey and not a clash of temperaments (pessimism vs optimism).
It might not solve everything, but maybe it's somewhere to start.
This is Dr. Phil saying good night and god bless.