One of the most effective weapons in the struggle against apartheid was an economic boycott. Another was the sporting boycott, which meant that South Africa couldn't pretend it was a normal society. It's equally important that Israel cannot pretend it is "normal" either to its own citizens or those of other countries. Yesterday's protest reminded both Welsh and Israeli football fans that there's nothing normal about Israel.
When they tear down the walls and treat Palestinians as equals, they can play football in peace.