I entirely see where you're coming from and do agree, however it does IMO provide a clear "line in the sand" to allow us to start to take that action. We should, as you suggest, have started some time ago, but for whatever reason did not do so. This marks something new and I believe would be something that most of the public would agree on as being an appropriate response.I'm fully on board with punitive sanctions against Israel for the atrocities it continues to unleash on Gaza - but it would be a huge stain on our nation's character if we for months turned a blind eye to the slaughter of tens of thousands of innocents, only to be finally prodded into reaction by the tragic killing of one or two of our own people.
After all, if any other nation on earth took out multiple British aid workers in such a manner you can bet we would be imposing sanctions on them faster than you can say "pariah".