The host, Mark Goodman, commented that it is absolutely the artist's right to protect their property rights. The listener then basically said "but can't YouTube police it's own site and take down unauthorized content? They seem to be able to do that pretty quickly on all sorts of content that they think is offensive..."
The hosts pause, laughed nervously, made a comment like "well...there are discussions like that going on at the highest levels of government right now..." and moved to the next caller.
The truth, of course, is YouTube does not WANT to pull that content down because that's a key driver of traffic to the site. They LIKE that content even if it is illegal. In contrast, content that is legal but which they don't like, gets yanked.
The guy makes a good point