After reading some of the links I can take a couple of guesses as to what is going on.

The intent is probably really to poison the previous edition, but I do not see any indication that the new license is any more restrictive than the old license.

The comments are almost certainly a response to Paizo's Pathfinder game, which is basically a remixed D&D 3.5 that Paizo is launching in beta with some fanfare, and promising to support and run their own products.

The comparisons with open source and GPL are not entirely correct because derived products in the RPG world are rarely available for free download. It is as if Wizards created D&D 3.5, and Paizo is trying to take on the job and profits of maintaining and extending 3.5.

This will cut into sales of 4.0, so Wizards doesn't want to allow that. It would split D&D into two camps with differing products and fanbases.

I am a bit confused. I thought that most TOS tend to allow the ISP to terminate your contract without really needing to specify a cause.

Specifying that they will do so if you criticize AT&T seems to be the legal equivalent of twirling their moustache and saying "Har, Har, Har."