I'll hold off on speculating on *why* Amazon UK took it down (has Amazon US done so as well?). But good for them that they did so.
They probably removed it for the same reason Channel 4 News blurred the image when they showed it - they are less idealistic than we are and prefer a quiet life. For Amazon, I completely support that, they exist to sell stuff, they have no reason to get involved in a censorship debate. I was a little disappointed (although not surprised) that Channel 4 News didn't stand up for themselves and show the image (after consulting with their own legal team) so viewers could make up their own minds about whether or not it should be on Wikipedia - censorship is as big an issue for the press as it is for us.