I'll second this. I would argue that .Net Core's package/dependency management in general is way better than Python or JavaScript. Typically it just works and when it doesn't it's not too difficult to fix.
It's also much faster to install packages than npm or pip since it uses a local package cache and each package generally only has a few DLL files inside.
what's wrong with nuget? I have to say I like the "I want latest" "no, all your dependencies are pinned you want to update latest you gotta decide to do it" workflow. I can think of some bad problems when you try to do fancy things with it but the basic case of "I just want to fetch my program's dependencies" it's fine.
I'm guessing they only used it 10 years ago when it was very rough around the edges and didn't integrate well with the old .NET Framework. It was quite bad back then.. but so was .NET Framework in general. Then they rebuilt from the ground up with dotnet core and it's been rock solid since
Or they just hate Microsoft, which is a common motif to shit on anything Microsoft does regardless of the actual product.
The project I'm on right now originally had the nuget.exe saved in source because they had to manually run it through build scripts, it wasn't built in to VS until VS2012