That does depend on the situation. We know that google wanted to buy Github, so a (very unlikely) motivation could be that microsoft bought github to "protect i

That does depend on the situation. We know that google wanted to buy Github, so a (very unlikely) motivation could be that microsoft bought github to "protect it" from google, or in case of no deal happening, financial instability. That being said, we have no way of knowing what the true motive of the move is - being sceptical/critical is indeed the correct reaction.