There's a difference between buying something designed by a person that you know is a pedophile, versus buying something designed by a pedophile before you know they're a pedophile.
You didn't actively support their lifestyle if you didn't know about it. And selling something you already bought when you find out after the fact doesn't make much sense to me. Especially since selling, not selling, or whatever doesn't further enrich the person in question.
Saying you will sell GB is akin, in my mind, to posting on Facebook that you support France after the Paris terror attack. Symbolic, but meaningless.
If you want to have an impact, there are real ways to do so. Selling a Pin he designed before this came out doesn't make much sense to me.