“And? Why are their lives so sacrosanct whilst the poor saps at the bottom of the food chain are expendable?”
It’s just a practical reality that the leader of the country dying is a greater loss than an infantryman dying. That doesn’t mean one life is worth more than the other, but the consequences are greater for the nation.
If some country is run by a dangerous entity, it is much better to kill them than it is 10s of thousands of enemy grunts and civilians, not to mention those on your own side.
Besides, if Saddam Hussein could have organised Bush’s or Blair’s assassination, he would have.