Largely because it's Microsoft.
Everyone else does cross promotion of their products but some people hold a special place in their heart for hating on Microsoft. It usually manifests itself with frothing at the mouth, exposition about how they were sued as a monopoly, and they're the devil. It's as if Microsoft was breaking into homes in the 90s and swapping your Macs out for PCs.
Someone will respond to this post with a laundry list of complaints about them that they've had saved off in a .txt to counter posts like this.