Many if not most Washington DC employees have past experience as lobbyists. It'd be hard to find qualified employees if you excluded everyone with past lobbying experience. Also, most lobbyists aren't really bad people, I mean there are lobbyists who work on behalf of autistic kids or cancer research. Heck, NORML probably hires lobbyists too.
Ron Paul has probably set the record for number of house votes that went 434-1 or 1-434, where he was the 1. Not exactly a team player, that Ron Paul.