The human intelligence-stupidity dichotomy-coexistence does limit human capacity for both intelligence and stupidity. Human intelligence is limited, we are not super-intelligent beings, thus stupidity often degrades intelligence via idiotic ideas.
Supposedly "intelligent" "humans" while capable of advancing knowledge, or perpetrating harm, are not capable of overly dire existential risks. The stupidity factor of humans does bring us close to the brink but the intelligence factor keeps idiocy in check.
Steven Pinker claims violence is decreasing, which I attribute to the decrease of stupidity. Intelligence is increasing, accelerating. The increase of intelligence makes supposedly smart people less inclined to engage in religious idiocy. Religion is decreasing. A truly intelligent person would be capable of great harm but their intelligence will have reached a level where they see the folly of engaging in idiotic ventures, thus no terrorist sarin events or wasted years reading the Bible.
In an ideal world science enthusiasts would be ruthlessly logical. They would be immune to religious or other nonsense. A passion for science unfortunately does not make a person immune to stupidity. For example #Einstein while intelligent in many areas idiotically stated: “Science without religion is lame...”
Perhaps we can forgive Einstein's “lame” statement because he also reportedly stated: “The word god is for me nothing more than the expression and product of human weaknesses,” which he elaborated upon by stating the “primitive legends” of the Bible are “pretty childish.”