The usual explanation is "four freedoms" and giving users freedom.
Leveraging network effects to create a communist shared ownership of the means of production is the honest explanation of the GPL, and that has nothing to do with 'freedom', and everything to do with network-enforced Marxist ideals.
> * It's that government-granted monopoly that allows control over other people's means of production. The solution to your problem is simple: fight for its elimination.*
I have no problem with copyright, and I don't want to forcibly eliminate the GPL. I'd be happy for it to die an honest death after careful and rational consideration by the industry.