We’re talking about the UI here, not the binary executable. Finder was extensively reworked in 2001 from the file manager in NeXT to be much closer to the original Finder, and most of the complaints here are about UI decisions taken from the original Finder, released in 1984. That predates Windows (not just Windows Explorer, which is from ten years later), Nautilus (created by Andy Hertzfeld of the original Mac team to be like Finder!), and the Unix variants, even the venerable xfm, which dates from the early 1990s.

The PARC interface (by which I guess you mean the Xerox Star) had significant differences, and I think would confuse any modern computer user far worse than the Finder. The Lisa was closer to the Star but the Mac used a simplified model that just equated files to icons.

Source: I lived through this process and used all of these for actual work at some point. The Finder’s influence on GUI file management was rather like the iPhone’s influence on phone management.

> Finder was extensively reworked in 2001 from the file manager in NeXT to be much closer to the original Finder, and most of the complaints here are about UI decisions taken from the original Finder, released in 1984.

Why would they ignore all the lessons learned between 1984 and 2001?

That's the reason why most people complain about Finder today.