True, but he mentions .NET development is Windows first, and even mentions that you have "some IDE's that work with it, like Rider". He kind of said it without mentioning the specific IDE.
I don’t think it is fear. We are transitioning our decades old software to .net 6 right now. It will approximately take a full year (we are about halfway done) since we use WPF, WCF and a lot of Windows native APIs. And in the end we will be on 6-windows and not the cross platform sdk since we can not get rid of WPF without major UI rewrites.