Packaging tools for language/ecosystem X written in another language Y are always a red flag. They had to reinvent a bunch of wheels, such as parsing metadata, and they probably did it badly.
See also: uv.
See also: uv.
The same goes for typing.. mypy (written in Python, and contributed to by Guido himself) performed so poorly that they had to invent a bespoke compiler for it (mypyc). The other options written in Rust or node are much more performant.
Another example: the golang port of the Typescript compiler.
I agree with the take it's odd to write a nuget server in node, but the comparison to uv isn't fair. There's concrete reasons to choose a more performant language for the task.