This isn't true at all anymore for years! Microsoft acknowledged Linux won for server-side and since C# is primarily used as a server-side language they made everything work incredibly well on Linux.

I find that modern versions of dotnet seem to run better on Linux. And from what I see from Azure and from MSFT engineer blog posts, I'm assuming dotnet support on Linux is a higher priority than on Windows.

In any case, their claim that dotnet is a bad framework made me chuckle out loud. I'd like to see their impression of what a better framework looks like.