The fact that it includes the word "never" was the clue for me...

Which I responded to. Reading never as never is more of a misinterpretation than anything else.

Even if we accept that (even though a maxim that starts out "we should hesitate to" rather than "never" will be much less rhetorically potent), HR claims to observe a fact about the world: that malice is far less common than stupidity, or at least that it's profitable to behave as if that were the case. I've never seen that observation supported, in any discussion about HR. My own experience of the world contradicts that observation much of the time. Probably not most of the time, but enough to make it a mistake to stop thinking, as HR advises us to do.

In fact it's often wise to act as if one sees stupidity, even when one suspects malice. In that way one may tempt the malicious into overstepping. But HR doesn't say anything about actions, only about attributions.