One way to measure the impact of a death from illness vs. a deliberate attack is the impact on society. Since the goal of terrorism is to destabilize a society and instill fear, the ramifications reach far beyond the individual who died. Take a look at what happened to the stock market after 9/11. The resulting fear was widespread and very disruptive. The ramifications of doing nothing when someone dies of a heart attack are minor, doing nothing when an external force kills a citizen can be far reaching.
The second reason is justice. A person dying from a heart attack is a "natural" death, nobody (except possibly the victim themselves) contributed to the death.
Using the logic of the grandparent, the world should have said "Let's ignore the Rwandan genocide because more babies die of diarrheal diseases."
How would you have reacted to 9-11? Just shrugged your shoulders and said "it's only 3000 people?" Maybe the same for Pearl Harbor? If so, you'd likely be speaking German or Japanese now.
The second reason is justice. A person dying from a heart attack is a "natural" death, nobody (except possibly the victim themselves) contributed to the death.
Using the logic of the grandparent, the world should have said "Let's ignore the Rwandan genocide because more babies die of diarrheal diseases."