Rent in the economic sense is distinct from rent in the sense of payment for temporary use. Ben is knowingly stating that rent - in the economics sense - is more destructive than theft.

Theft is indeed bad for the economy. Wealth is illegitimately transferred from one individual to another, and the one from whom wealth is stolen suffers. There is no intent to avoid this subject.

However, rent-seeking in the economic sense destroys wealth my using it in pursuit of theft. Extortion is a subset of rent-seeking as described in the article above. Racketeering was the first example given.