I think it is probably a combination of things.
They don't have as much control. I noticed that those that hosted BS were becoming less gracious about it. They were tired, and didn't want people wandering through their houses, wanted them to leave so they could get rest. Fewer people were even offering up their homes, and we had a shortage. One woman I know had the BS pulled from her house, because she had to get up at like 4 in the morning, and didn't like to have goody nights once a month---she was tired! In the past, I think most hosts justs tried their best to set these things aside and not express them---but today I think many are half awake and less tolerant. The end hasn't come, and it's been 100 years, and they are more cranky.
These internet sites are taking their toll. While a lot of individuals may not visit them, if just one in a small group has, the ideas can be passed along. And they can sit for hours and a comfy kitchen table, drinking tea and discussing them.
I noticed too, that BS groups tended to form tighter and more personal bonds with each other. Kind of like an extended family. I don't think the WT likes this as much now that they are losing control. These small groups build more trust in each other, and people are more likely to let their guard down and share those forbidden ideas.
I'm one that doesn't think the legal dept had much to do with it. My understanding is the home owner assumes all liability. So if you trip, you sue the them and not the WTS.
Or perhaps it's the reason that all JW's are sure of. THE END IS NEAR AND JEHOVAH IS PREPARING HIS PEOPLE. HE IS TRYING TO PROTECT THEM FROM DETECTION BY THE WILD BEAST. IT'S CLOSE NOW!
However, I tend to doubt the last reason listed. I'm just not faithful that way.