>Do you know of other surprising examples of sites getting takedown request because of "immoral behaviour" (or whatever the name is)?

They banned vimeo for ISIS video just day before github. They also banned youtube and vkontakte before.

>Still, I'm surprised they bother with github being such a specialized website.

They are just targeting all popular resources on purpose to make public case.

Vimeo works fine though (as is youtube, or course) :)