Of course not, but I think Microsoft is the biggest example of a huge company turning around from "open source is cancer" to "let's try to do open source for some things".

I'm sure there are more examples of companies embracing open source after previously looking down on it, maybe you have some names handy?

It's not important what any other company has done. Motivations and end goal is. Microsoft's embrace might be a vampire's.

Long term, the involvement of companies like Microsoft in OSS and OSS communities might be damaging, not beneficial.

Microsoft embracing things is definitely not a good thing. There are plenty of reasons to put irrelevant stuff on their very own Github, but altruism is very down on that list when it comes to enterprise, especially Microsoft. Fool me once and all that. Microsoft might be pioneering the wolf in sheep clothing model, but I for one, better liked the honest, openly hostile approach.

I'm going to reconsider my point when everyone can compile their own fork of Windows and Office.