Once again that is Steve Ballmer. If this was a whole corporate belief it would have been true through the whole company and its policy and it wasn't.
NOT defending the bad parts of MS but people treat MS as the evil empire when it was a divided HUGE company. Inside MS there were plenty of positive open source people and projects inside of MS. https://en.wikipedia.org/wiki/History_of_free_and_open-sourc...
I believe the Anti-MS is way out of proportion and distracts from worse offenders. Look at Oracle that company is the devil to Open/Free software and people will still run Oracle products all the time. (Stares at my own OpenBox for use with Vagrant on my Windows machine next to me). IBM and their incredible patent farm (IBM year in and year out the number one patent company in America).
Apple is the polar opposite of the open source movement. Apple has been guilty of price fixing ebooks, patent misuse and the copyrighting of design and slide to unlock. Apple does not work with the community but behind high secret walls. You share a secret and they might send the police after you or sue you. They black list reporters that share an opinion that is negative to Apple from access to the company, events and products.
So yes MS has made many bad moves but I wouldn't even say they are the worst. If you take out anything Steve Ballmer has said they are actually were better then most.
Open Source Movement has won and we should celebrate the victories. SQL Server on Linux I wouldn't have thought this in a million years and C# opened. These are amazing days.