There have been Windows installers for quite a while: http://gimp-win.sourceforge.net/stable.html You'll see the 2.6 stable is available at the top and 2.8 RC1 is at the bottom (I'm guessing 2.8.0 will be up by week's end.)
I know, I just thought the 2.8.0 would be made available at the same time.
Why should they care for the 85% market when they can target the 0.95% market?
There are a lot more alternatives on Windows though, Paint.net and Photoshop being obvious choices. With Linux and similar Gimp is really the only image editor. That I know of anyway.
Those Linux users get all the breaks!
I think only GIMP would say GIMP 2.8 is here! And yet there isn't a Windows installer for it.
If I were them, I would have waited a few days and gotten the Windows installer together first.
The Windows installers are prepared by a separate team, not the GIMP developers. There's really no use in getting upset that another platform you don't care about got it before you.
I'm pretty sure the Windows installers are made by another individual. Not the GIMP team.