I'm not complaining about it, though? I'm arguing against this statement in isolation:
> Locking it down to specific "best we know of as of this moment" prevents people from easily using materials we know to be incorrect, which in turn also prevents people from sending invalid bug reports.
Which, whether it actually pertains in fact to MAME or not — not my concern here — would be a bad idea on its face, and one that I would want to discourage other emulator developers (who may well be reading this thread) from getting the idea is "a thing that is okay to do because MAME does it."
You really should learn more about a product before you complain about it.