It was a silly delusion. Very silly, but Throttle still believed it.
A little part of him thought that there was a limit to human evil, that a human could only do so much harm before they reached a invisible limit. Part of that was from the only humans he really knew were good- Charley, hell, she fixed their bikes for free, and Andy fed them for pennies. They were really very good people, and Throttle just subconsciously thought that so was the rest of humanity.
God, was he proved wrong.