So far as I know, parliamentarians are hired to advise on parliamentary procedure. If an organization has adopted RONR and hires a parliamentarian to advise on its use thereof, what is the question to ask? Parliamentarians aren't hired to advise on whether or not RONR should contain some rule or other. Certainly parliamentarians aren't hired as consultants on accounting or law. If an organization doesn't like that rule, it is free to adopt a different rule.
A parliamentarian could be legally said to skate on thin ice when advising that a motion is not out of order simply for violating substantive law - if someone were to mistakenly think that parliamentarians are supposed to give legal advise.
So, when we're talking about RONR, then, many parliamentarians do know what they're talking about. If they were to talk about accounting, many would not. But the rule under discussion here is not an accounting rule, nor is it a law. Parliamentarians, I agree, should refrain from saying the reason for this rule is about liability for the corporate officers as opposed to the auditors. I certainly wouldn't make the assertion given here, as it makes no sense to me. I also wouldn't make one that does make sense to me, formally, if it's in an area I am not familiar with, such as accounting or law.
I've been told that the American College of Parliamentary Attorneys advises against including the name of the mover of an original main motion. Most organizations, though, adopt RONR, not the recommendations of said organization. No one claims that following RONR is a safeguard against liability, other than that arising from not following your bylaws/parliamentary authority. This question seems similar, if less important.
The key here, for most organizations, is that one should not adopt an unaudited treasurer's report - although organizations remain incredibly stubborn on this point, in my experience. I've always looked at that one and said - well, of course there shouldn't be a vote on adopting that, how on earth do I know? I don't look at the books, how do I know if the treasurer is correct or not, in order to vote? An audit report, on the other hand, makes sense to me for adoption, since an outside expert delivered it, and we now adopt it as the statement of the body. That doesn't seem to me to be about protecting incoming treasurers or corporate officers, but just saying "yes, we see things this way as of this moment."