You're reciting the requirements for the CONTRACTOR, not the worker. The Plumbing Contractor has to be licensed to do work, yes. The workers for the plumbing contractor may or may not be licensed based on what they hope to acheive in their own lives, ie. with respect to pay, advancement, independent work, etc.

The company he works for IS licensed, as far as he says. He himself is not licensed. Educate yourself further instead of citing some left wing blogs attempt to discredit a guy who spoke his mind and caused Obama to reveal a little more about his true philosophies than he wanted for public consumption.