The first edition of Peacemaker laid down the gauntlet in terms of substance, alluding to other superheroes from the DC universe in a surprising way. Peacemaker enters into a disagreement with Arthur Curry regarding Aquaman, who is portrayed as a real person in the Peacemaker universe and accuses him of indulging in improper practices with fish at one point in the episode.
Later, Peacemaker taunts Superman of having a faeces fetish, and then gets into a fight with Batman, labeling the Caped Crusader a "p—-y" for not slaughtering civilians. It's maybe unsurprising that DC had a problem with Peacemaker hurling such vile obscenities against other well-known characters in their books. DC had a specific issue with Peacemaker's Batman slur, as series creator Gunn said to THR's TV's Top 5 podcast (via TVLine), and admits to being perplexed by their line of logic when it came to what stepped over the line and what didn't.