Several countries have said they will act on the warrant should Netanyahu show up inside their borders. Italy, Canada, and the UK have at least said they would. It's unlikely they'll have that opportunity, having forwarned the criminals. However, there are strong forces moving to arrest Netanyahu inside Israel too, so, whether Israel agrees the rest of the world has the right to arrest them, the rest of the world will decide themselves what happens on their dirt, and Israelis will decide what happens on theirs, and Netanyahu may finally end up held responsible for what he's done, or at least some of it.
Thanks!