It means that a lot of people that you are putting down will see you as their prime target. This goes with the territory.
If KM would have taken a job as a programmer somewhere I highly doubt that this would have happened. After all, he is minting his reputation as a former bad guy, nobody forced him to do that.
If he had been a white hat all along it would be different, but a burglar complaining he's been burgled is a bit hypocritical imo.
I guess it sucks being on the receiving side.
Basically all these little jerks do is make him look silly, personally I wouldn't even bother to respond to them, just take it as praise and laugh at it. By taking it so serious he is actually fanning the fire.