I'm not sure I would be so quick to discount her chops. Bonzo was a very good drummer but his playing was a special style which made him more unique. Of course he was more powerful of a drummer. KC was a very accomplished and well rounded drummer.I think he's probably right.. Bonzo smacked the heck out of his kit.. and she was anorexic (which sadly led to her demise).. and probably would have passed out tying to match his power on the kit.. not to mention his technical chops.
but she was a much better singer than the mighty Bonham! ( and an accomplished drummer as well).. but polls are often nutty in any case.