Where have you been… under a rock 
Disclaimer: I am a Linux user
Since day one that I believe that Github acquisition is part of their long term strategy to get back Developers into the Microsoft sphere, not necessarily ecosystem. I mean they want you to use as much as possible their products, free and paid ones, no matter what platform you are in, and without trying to convert you.
A good example of a free product that they are successfully locking in all the developer community is VScode, and with this and Github acquisition they will try to make as simpler as possible to deploy any code into Azure, and that is why they are doing all they can to embrace other communities of programmers, not to fight them as in the past. They even have now the Linux subsystem running inside of Windows.
But the best of all is that they are now members of the Linux Foundation, contributing with money every year, that is used for many things, being one of them to pay Linus salary Could you imagine that to become a reality in the past?