It's not that Debian lacks things to do, and they are being picky about the licenses: it's that some projects are rather negligent about their terms of licensing, sometimes downright dumb, and then somebody like Debian has to untangle the mess they created.
It isn't really that "someone like Debian has to" generally - Debian has to as a large part of their reason for existing is providing a stable, reliable, and predictable system: both in terms of content (code and other assets) and license to use said content. If they aren't picky about these things they are not staying true to their stated aims (and a number of their users would be unhappy).
> it's that some projects are rather negligent about their terms of licensing, sometimes downright dumb
Actually true. You will find competent developers who will change the license across their web app codebase from MIT to AGPL on a whim, saying AGPL is just the same as GPL.
I find legal stuff seriously interesting but also seriously scary.
