Interesting, I have win7 32bit starter edition on my acer aspire one netbook and both my gadgets are still on the desktop and working. Though the win7 32bit starter edition is much crippled, I don't believe it has the Sidebar feature, but you can get gadgets (or I found a way).
But if you try to get more you get the Because we want to focus on the exciting possibilities of the newest version of windows, blah, blah, blah.
There is little on that page about security other than Gadgets installed from untrusted sources can harm your computer and access your computer files. Great so Microsoft is saying that the Windows Desktop Gadgets is an untrustworthy source, well I can fully understand that as I don't completely trust microsoft's sharp practices.
If their really is a security issue, what is wrong with them patching it.
So I rather feel that this is more to do with them trying to push win8 metro style apps.