Rabble's motivation is incredibly petty. She basically blame Miles for something he had no control. And a lot of fans thinks (no without justification) this motivation is lame. But think about it: blaming the hero for something he never did or had no control and attacking him instead of someone who deserved it, knowing said hero's secret identity and using it to target his loved one...is what Venom did the first time he fight Spider-man.
