"I'm heartbroken about what's happening in my country," Cook said in tweet Sunday. "The definition of insanity is doing the same thing and expecting different results. It's time for good people with different views to stop finger pointing and come together to address this violence for the good of our country."
Cook is no stranger to voicing criticism of government activity he sees as detrimental to the US. In 2017, Cook spoke up against President Donald Trump's effort to close the US to immigrants from predominantly Muslim countries, telling employees in a memo that, "It is not a policy we support."