Not really trying to protect Microsoft here but them companies are all the same, just different degree of "success".
The argument is that if a language is developed/mainly contributed by a single company there is an inherent risk of that language being suddenly discountinued or lacking features that are needed by other people/companies.
At least that's how I understand the critics against microsoft in this case.
Funny how nobody seems to give pile on Google for how it handles Go here...
Thanks goodness for Linux and the web (and later mobile computing which MS failed to dominate) to pull us away from the brink of an MS monoculture.