OK then: Your reasoning is fallacious. You've equated coping copyrighted works with witholding changes to a GPL program based on the observation that they're both released under a set of conditions.

The point is you haven't taken in to account the relative validity of the conditions. You can't equate them simply because they are "conditions".

The conditions of the GPL are (put very simply) "you must share". The conditions of JB's work are (put very simply) "you must not share".

You don't get to compare instances of infringing each of those rules unless you can demonstrate that a requirement to share has equivalent ethical validity to a requirement not to share.

If you're going to say "If you do X don't be pissed if I do Y" then the onus is on you to show that X and Y are equivalent.