Allow sellers to Absorb Sales Taxes

I understand that there are new tax rules for EU and UK-based customers, and that Beatstars simply adds this tax onto the customer's bill. But I don't see why this tax could not just be absorbed by the seller, if they choose to (like with the Marketplace fee). I understand that taxes differ by territory, but I don't see why you couldn't just calculate the tax and then deduct this from the producer's share. The surprise fee is losing us a lot of customers!