He is pointing out double standards.
Kevin Hart scored a big win when he was offered a hosting gig by the Oscars. This achievement was undercut by the resurfacing of homophobic tweets for which he issued a non-apology and eventually stepped down from his role at the upcoming award ceremony. In light of this chain of events, Nick Cannon felt compelled to remind people of some of their comedy sweethearts' dalliances with similarly offensive content.
He shared old tweets from Chelsea Handler, Sarah Silverman and Amy Schumer, all of which have experienced major success in their respective careers as comedians and actors. Cannon seemed to question how these figures have continued to sustain positive trajectories in the professional realm by despite their use of homophobic slurs in the tweets he reposted.
Cannon is clear about his stance. He isn't trying to shame these female comedians for these words as much as he is highlighting the hypocrisy of both the entertainment industry and the public. He does not condone the rise of political correctness. The comedian would not mind people unearthing some of his old tweets either.
"Nope!! You know I’ve been saying fucked up shit since twitter started! I don’t play that politically correct bullshit! Fuck politics!! Only Truth!"