It is like a child giving me a shiny rock because they like the pie I made better. Am I not to blame because I understand the value of the diamond better than the child and use the information asymmetry to my advantage?
If that's not the case and you really would only part with the pie for that high of a price, and no other pie will do for the child, then what is there to complain about? How much do you think it costs to buy a pie made by, say, Gordon Ramsay? Feel free to replace with someone who is actually a good chef and not just a famous one if I made a poor choice.
To me it is like asking should we allow animals to kill each other. Not only can we not really stop it, even if we could it would kill any carnivores.