Clueless coders
I bet most developers don't even realize they're actually using Microsoft's cloud platform on a daily basis, because, well, GitHub is owned by Microsoft, and is hosted obviously on Azure. So, in reality most likely the majority of developers are actually using Microsoft's cloud platform, and more than they realize. But even if they wouldn't, it's mostly irrelevant what cloud platform developers are using, because they're an irrelevant minority amongst cloud users. And JetBrains' survey is not representative of the developer community anyway.