There isn't one. It's just increasingly unnecessary.
I, personally, have an issue with people taking millions of LOC of software written by other people and given away for free, slapping a logo on it, and selling it to people who don't know better, but thre licenses generally don't prevent carpet-bagging.
IMHO, selling an OS your organization built most of is fine. Selling support, or hosting, is also ethical. Selling Libre software is not.