Yeah, the issue is not “Microsoft’s usage of the XML format”. The issue is that they blatantly bought their format’s standardization, and then intentionally released an implementation that substantially deviated from the specs, making sure that MSO was the only “compatible” implementation.

The Big Lebowski is the pinnacle of humour! Now get off my lawn!

It’s a scene from The Big Lebowski, right after The Dude got tortured with a marmot by German nihilists. Walter focuses on the legality of keeping a marmot as a pet, which is obviously not the main issue.