load limits are generally specified in the construction rules and therefore there is no further need to explain the limits in the RFM
But you could make the same argument for fixed wing... Normal Category means 3.8, yet the limits are stated explicitly in the POH. It wouldn't seem THAT hard to include an explicit limit in the POH for a helicopter - especially since, from the rest of the thread, it would appear that in fact lower limits do exist.
As any instructor should know
Ah, but if they all did, it would deprive you of the opportunity of telling us all what a superior person you are.