Human mental capabilities don't seem to be well characterized - thus when people say 'intelligence' it's unclear what they're talking about. Case example: John von Neumann, who surely ranks high on anyone's list of 'most intelligent humans of the 20th century'. Brittanica:
> "Von Neumann insisted on the value of game-theoretic thinking in defense policy. He supported development of the hydrogen bomb and was reported to have advocated a preventive nuclear strike to destroy the Soviet Union's nascent nuclear capability circa 1950."
So, if humans destroy modern civilization with fusion bombs and are reduced to a Stone Age existence on a radioactive planet, will visiting aliens say, "Gosh, wasn't this a stupid species? Clever, yes, but not very wise."
> "Von Neumann insisted on the value of game-theoretic thinking in defense policy. He supported development of the hydrogen bomb and was reported to have advocated a preventive nuclear strike to destroy the Soviet Union's nascent nuclear capability circa 1950."
So, if humans destroy modern civilization with fusion bombs and are reduced to a Stone Age existence on a radioactive planet, will visiting aliens say, "Gosh, wasn't this a stupid species? Clever, yes, but not very wise."