Scientists do the same thing and expect different results whenever their first runs are yielding results outside the expected experimental parameters; they figure they didn't nail down some variable or pollutant so they do it again expecting different results. In this case it's not even slightly stupid and self destructive, much less insane.
Generally this sort of repetitive mistake making is symptomatic of bad thinking and human futility, but it isn't even a neighbor of insanity. Looking at this world and concluding that obvious mythology is capital T Truth is way more insane than repeating mistakes and hoping for better outcomes, and loads of people still do that.
Some repeating mistakes are indicative of a pathological issue - sure, and some pathological issues are a matter of what we point at with the word 'insanity' -also true; but it is a distribution fallacy to push this all the way through to claim the cliche is true.
Next time you're about to say it, why not say something intelligent instead.