"Fred" - any cyclist who is not like you to make yourself feel better about your cycling.

If you are on a carbon race machine, a Fred could be an unfashionable utilitarian cyclist in street clothes with a rubber band around his pant legs. Or, a Fred could be someone in a full pro kit on a carbon race machine who rides a bike path at 10 mph.
If are on a lugged steel touring bike, a Fred could be anyone else on a bike.

Generally....a Fred could be anyone you'd say "Omigawd...I'd never be caught wearing/doing/riding THAT!"