Story highlights Bill Clinton campaigned Friday for his wife in Pueblo, Colorado

Melania Trump campaigned Thursday for her husband Donald Trump in Philadelphia

Washington (CNN) Former President Bill Clinton expressed disbelief Friday that Melania Trump would denounce cyberbullying given how much her husband antagonizes others on Twitter.

On Thursday, Melania Trump, in her first speech on the 2016 trail, said she'd work to improve a social media culture that she said has gotten "too mean and too tough" if she became first lady.

"Yesterday, I never felt so bad for anybody in my life as I did for his wife, going out giving a speech saying, 'Oh, cyberbullying was a terrible thing,'" Clinton said at a campaign rally for his wife, Hillary Clinton, in Pueblo, Colorado. "I thought, yeah, especially if it's done at 3:00 in the morning against a former Miss Universe by a guy running for president."

In September, Republican nominee Donald Trump took to Twitter around 3 a.m. ET to slam former Miss Universe Alicia Machado, who at the time became a prominent surrogate in Clinton's campaign.

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