Edited the post to show where I got the maxim.

Doesn't really make sense to me and would lead to some very weird conclusions.  

For example, I'm a manager and one of my staff talks to me and says this report takes a very long time because there are many manual steps, I believe we could automate these steps by using software X which I've used in a previous role and costs $Y.  By the logic of this maxim I should ignore the proposed solution AND ignore the initial complaint.

Because they proposed a solution, now I should think it less likely that the report takes a very long time?  Seems totally nonsensical (or I'm not understanding what you're actually saying).

My answer for why this may happen, conditional on this actually being generalizable, is that people have surprisingly good intuitions that something is off or deserves praise, but when forced to explain, the brain makes up a plausible reason, instead of the true reason that something is wrong.