Show me where he said that? He said no such thing he just stated that MAME is very simple, its users that seem to complicate it for no obvious reasons. Generally it is just like other emulators, you download a pack of roms and you download the emulator, you then tell the emulator where the roms are, and set your controls/options, again just like any other emulator up to this point. The only difference here is matching the emulator version, but thats as simple as downloading the version you need (every single release ever is available from here MAME | Previous Releases (mamedev.org) so getting the correct version is no different than downloading any other emulator). And as long as the romset you downloaded hasnt been tampered with and had things removed then it contains absolutely everything you need, its when users start saying well i dont want all of this and start deleting games that issues occur, as they tend to delete what they think are unrelated games, when in fact you may have dozens, sometimes 100's of other games that rely on files within the zip you deleted.
Keep it simple, get a split/merged/non-merged romset, get the correct emulator for it, if you want to keep your roms outside of the emulators folder tell the emulator where to find them, setup controls/options if needed, as i said earlier, really no different than any other emulator, if you are doing other things that then complicate this very simple setup then you cant really blame that on the emulator, as you are doing things it is not designed to do, and thats on you, not the devs of MAME.