First of all, it's not a good analogy. Software licenses are a contract that you can choose to agree to, whereas laws give you no choice.
Second of all, it is highly debated wheter the restrictions imposed by the GPL are a worthwhile tradeoff; while noone in their right mind claims anybody has a right to own slaves...
And lastly, by comparing the GPL to laws against slavery you are trying to evoke certain associations, much like stallman uses the word swindle instead of kindle -- those are just cheap tricks that distract and make fruitful discussions hard.
Second of all, it is highly debated wheter the restrictions imposed by the GPL are a worthwhile tradeoff; while noone in their right mind claims anybody has a right to own slaves...
And lastly, by comparing the GPL to laws against slavery you are trying to evoke certain associations, much like stallman uses the word swindle instead of kindle -- those are just cheap tricks that distract and make fruitful discussions hard.