Yes it does. That is (partly) why those who love music often hate (too much) compression.

then the premise of the article is inherently flawed :(

If YouTube compensates for this (lowers the volume of tracks that have been mastered loud), then it removes the original motivation for doing so.

This is why the 'Happy' YouTube mix is less loud than the CD version linked to - the author asserts that the studio has done this because the incentive to apply dynamic compression on YT is now gone...

Dynamic range compression does destroy some information, but you can still change the final playback volume.