The analogy was to C# and Objective C, not to those other languages. The argument went

1. Facebook might abandon Hack at some point

2. No, Hack is like Objective C and C#, which Microsoft and Apple support just fine

3. No here is how Hack is NOT like those languages, community support is not important to facebook like it is for ObjC and C#.

So how Microsoft treats other languages is completely irrelevant to that particular point, and actually supports what Marco is arguing here, since you're implying that programming languages might be abandoned even if community support does matter.