In essentially every society of which I am aware, and certainly ours in the 21st century, it is common action to almost always accompany vocals with instrumentation in one form or another. But we're not talking about basing our general practices, policies and system after the society's standard - we're talking about common, everyday actions that may or may not have other actions regularly tied to them (e.g. microphones tied to speech, instruments tied to music, etc.); and in that regard I honestly fail to see how the papacy example relates in any way. Furthermore, what I was wondering when I made the analogy is how it can not be "OK" - for why can the legitimate aids for preaching a sermon and staying through a sermon be determined simply by asking about common culture's practices of speaking and sitting in general, but the legitimate aids for singing praise to God cannot be determined simply by asking about common culture's practice of singing in general (since you seem to be saying it can only be determined if singing specifically to God was a common cultural practice)?