Its members are made up of mainly non-web technology companies that sell expensive products and are worried about piracy or counterfeiting of those products: Oracle, Microsoft, Adobe, Intuit, Symantec, etc. Conversely, they don't run user-generated-content sites like YouTube or Facebook, so aren't worried about the problems with weakening safe harbors.
GPLv2 does not contain the explicit patent grant that are part of why GPLv3 was created. And I very much doubt the courts will consider "or later" to include the patent grant.
The code in question seems very peripheral (something about using Firefox for configuration), and have received zero comments on the developers list. I would be very surprised if Microsoft had any other motivation for the release, than to make the engineer who worked on it happy.
However, it is probably not an accident that they choose the version of the GPL without a patent grant.
Also, unless I'm very wrong, the terms "GPLv2 or later" means you can use the software under v3 if you prefer to use it that way. The only way to block the explicit patent grant (but stay will the implicit one) would be to license it under plain v2.