I honestly think that if Maria could've beaten Serena from time to time, these kinds of things wouldn't happen. It's the combination of seeing Maria fall short over and over and then having to deal with the endless barrage of mockery, insults, and bullying from the Serena fanbase. It gets tiresome after so long and there's really not much you can do about it other than ignore it or leave. And because the rivalry on the court is so lopsided, Maria fans have no ammunition to combat the classless thugs on the forums. And Serena's continued domination will keep feeding the trolls and work them into an arrogant frenzy.
I may be looking too much into it. Maybe Stoner and others just lost interest for other reasons. But, I have to admit, tennis hasn't been that much fun over the past year since Serena started doing her thing, winning everything in sight and Maria going 0-7 against her. It makes it harder to keeping generating enthusiasm with each tournament when you know the outcome is likely disappointment again. And this Wimbledon is just the latest blow.
So, basically, it's all Maria's fault.