Actually it is quite true.
I have favorite component directories that I can't delete. No option... Still a bug. If the directory no longer exists we should be able to delete it from favorites. Period. Having them persist and junk up the list is a bug.
And yes Sketchup has other bugs they have not addressed. For instance the use of "/u" in directory file paths that breaks dynamic components. Pretty much makes dynamic components useless for anyone on windows who uses the "/Users" file directory, which is most everyone...
That bug has also been around for years...