Normally, I'd give context--but something tells me I shouldn't, so I'll just ask you this:
You know what went on in Bro Bots, yes? (If not, go look up the summary on Random Action Hour) How is ROCK the one to "go bad in the end" there, and not Proto or anyone else?
I think what they were implying was that Rock went after the RMs...which he had every reason to do. Rock wasn't the one who plotted to assassinate a mayor, threaten to shoot that same mayor in the face, or try to replace the mayor, his staff, and Dr. Light with dead-eyed robotic doubles.
Same person doesn't think that RS-Roll is a "bad person" like her brother even though she defeats her fair share of RMs. Just so you know what kind of backwards antimatter logic I had to try and refute.
Roll and Proto try to comfort Rock, presumably after someone tried using that "logic" on him--or maybe distract him from flying into an unstoppable rage. Either way--not a very good day.