"but they also must know Azure is not stable enough"
In what universe is this true? Azure is the backbone of large things in corporate America, especially in banking and healthcare that you never even think about. Things a lot more important than someone's repo being inconvenienced.
Any migration will be painful, but to say Azure as a service isn't up to the task is just nonsense.
It wasn't for optics reasons; that was entirely coincidental. It was announced well before the GitHub acquisition that we were moving to GCP, primarily for better Kubernetes integration [0].
You've got enough rebuttal on your doubt of Azure.
But another issue with this comment is this:
> in RackSpace and AWS
As far as I can tell, they moved off RackSpace a long time ago. And they only use AWS infrastructure for peering, which makes sense with the amount of AWS machines that pull code from Github. The majority of the heavy lifting is done in Github's own data centers: https://githubengineering.com/evolution-of-our-data-centers/
Having it in RackSpace and AWS is bad optics, but they also must know Azure is not stable enough for something as large and visible as GitHub.
I expect this to be the first integration they try. Stockpiling the popcorn.