There are many, many reasons people might want to avoid the GPL that have nothing to do with wanting to get out of a legal obligation to publish source. The FLO

There are many, many reasons people might want to avoid the GPL that have nothing to do with wanting to get out of a legal obligation to publish source. The FLOSS world is filled with innumerable high-profile, very successful projects that avoided the GPL for reasons that had nothing to do with wanting to keep some things proprietary. Sometimes people just want to share software without making a political statement that they may not agree with, or imposing a legal and/or social burden on others (or assuming one for themselves). The adversarial, black-and-white, with-us-or-against-us accusations that some GPL advocates are known for are actually a big reason why many people don't like the GPL, and associate it with carrying a lot of baggage in addition to the actual legalese that defines the license.