Cook went on to slam U.S. lawmakers' inaction around gun control as "insanity" and called for bipartisan efforts on the issue.
A shooting Saturday at a Walmart in El Paso killed 20 people and wounded 26, while a gunman killed nine people and wounded 27 in Dayton.
Alan Patricof, founder of the venture capital powerhouse Greycroft and a Democratic donor, is calling on Corporate America to come together to apply pressure on Washington to crack down on guns.
"I think we need a hell of a lot more activity on the part of company leaders to come out and massively say, 'We've got to do something about this,'" Patricof said Monday on CNBC's "Squawk Box."
It's not the first time Cook has voiced his concerns about U.S. government policies.
In 2017, Cook sharply criticized President Donald Trump's executive order temporarily banning the entry of citizens from seven Muslim-majority nations. He also joined a group of tech executives in calling out Trump's transgender military ban, calling it "discrimination."