I would rather my code gets used and better the software ecosystem than I get paid for it. To that end, GPL is only behind proprietary in things that I wouldn't use.
I think there are loosely 2 groups of people who use liberal licenses: First, people who use it as a "sane default"; these people are sometimes unhappy when it gets used commercially. The second group is the people who explicitly and intentionally licensed it to allow the widest possible use; these folks are often if not always thrilled to see uptake even if there's no direct money involved.
