You've yet to tell me why freedoms have limits. At least why the freedom to trade should have limits. The drug analogy is silly when the libertarians make it and it's silly tonight. It's silly because there is nothing productive that comes from injesting mind altering drugs. There's no compelling reason to do drugs. There's no compelling reason to possess child porn or molest children, yet there are libertarian factions that believe those activities should be allowed. Let me ask you this, do you think there should be a limit on rich someone can be?
Can you cite one place on earth where there is free trade? How is it that the global economy is working without the type of free trade you advocate?
Because there is this thing called "Right & Wrong". If your definition of "freedom" is expressed with the phrase "every man does what is right in his own eyes", then you have anarchy. If you are an anarchist, then there is no point in reasoning with the insane and delusional.
At least why the freedom to trade should have limits.
Because "Free Trade" is a Utopian fantasy. It defies clear definition so that it is utterly impossible to implement. It is made up of selfish, materialistic and power seeking men who would just as soon use treachery and deceit than honest hardwork and creativity. Water seeks the path of least resistance, and so do those engaged in trade. If I could spend a lifetime to acheive a certain measure of prosperity under the guise of cooperative and honest "free trade", or I could achieve my material, financial, and power goals in one year of backroom deals and cheating; guess which one wins out? For "Free Trade" to actually work, each and every participant must want and value "Free Trade" more than any other lust or felt need. Only the invincibly naive and ignorant would feel that such an environment is begging to be formed.