The GPLv2 is not a contract. It is supported by no consideration.

[clarityabovecompulsion]

> by drinkypoo ( 153816 ) <martin.espinoza@xxxxxxxxx> on Monday October 
> 01, 2018 @10:21AM (#57403506) Homepage Journal

> >What consideration was given?

> The right to redistribute was given in exchange for use of the license 
> for one's own code. Something for something. What was your question 
> again?



Incorrect.

The permission to redistribute was simply given, gratis, by the grantor.

He asked for nothing in return, and, infact received nothing, not even a 
promise of compliance.

At a later date any of countless licensees might decide they wish make 
derivative works based upon the copyright-owner's property.

By law this is barred.

However the copyright holder here has magnanimously granted that the 
licensee is, contrary to the default rule, permitted to create and 
publish derivative works provided that they use the same license as the 
original work.

Here the copyright holder suffers a detriment. He is payed nothing for 
this forbearance (no consideration).

The licensee does not suffer a detriment: he had no right to make nor 
publish a derivative work to begin with.

The extending to him, of permission, is a pure gratuity.
He payed nothing for the change from "You may not create nor distribute 
derivative works" to "You may create and distribute derivative works 
under the same license as the original work".