BERLIN—Russian-born Max Maizenberg, a network-security specialist in Toronto, recently channeled his disgust with Moscow's actions in Ukraine into a lengthy post on Facebook, equating self-described Russian patriots with "congenital morons."

The post rocketed around the globe as his friends shared it with friends until his uncle, who still lives in Russia, caught wind of it and complained angrily in a call with his sister, Mr. Maizenberg's mother.

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