https://plus.google.com/+gimp/posts/cxhB1PScFpe

Here's the text if you don't want to click:
It appears that +SourceForge took over the control of the 'GIMP for Windows' account and is now distributing an ads-enabled installer of GIMP. They also locked out original owner of the account, Jernej Simončič, who has been building the Windows versions of GIMP for our project for years.

So far they haven't replied to provide explanations. Therefore, we remind you again that GIMP only provides builds for WIndows via its official Downloads page.