Seems to me that their '"indistinguishableness"
' -- at the level you're invoking it as something to protect -- is not and never has been the point of permitting individuals to post as AM nor is it an essential element of anonymity in the context of the Monastery.
Rather, the point, IMO, is to allow any persons to post what they wish, without providing any link between their statement (opinion, rant, slurs, facts, code, whatever) and their actual personal identities or, as you suggested earlier, any link between the statement and the writer's individual semi-anonymous handle (CountZero, ww, etc.) But AM is not an individual handle; it's used by many different (but equally anonymous) individuals*1.
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....or so we may presume, given the varying competence with Perl, English, spelling, grammar, and so on that we can readily observe.