I heard that it was perhaps recently fixed, but copying many small files was multiple times faster to do via something like Total Commander vs the built in File Explorer (large files goes equally fast).
People seeing how slow Explorer was to copy would probably presume that it was a lower level Windows issue if they had a predisposed bias against Microsoft/Windows.
My theory about Explorers sluggishness is that they added visual feedback to the copying process at some point, and for whatever reason that visual feedback is synchronous/slow (perhaps capped at the framerate, thus 60 files a second), whilst TC does updating in the background and just renderers status periodically whilst the copying thread(s) can run at full speed of what the OS is capable of under the hood.