Max was a much more competent agent/saner person when he began working for CONTROL.
His experiences as an agent got to him and caused permanent psychological damage. He and 99 are both repeatedly shown to have symptoms of PTSD (that are always Played for Laughs
), what with Max jumping and screaming "Don't ever do that!" whenever someone sneaks up behind him and 99 reflexively punching Max whenever he tries to sneak up behind her to kiss her.
Siegfried is an age-progressed Hitler.
And Starker is possibly an age-progressed combination of Herrmann Goering and Joseph Goebbels.
In one throwaway gag, one of the undelivered CONTROL messages reads "The British are coming". So they've been around at least as long as the Revolutionary War.