In 10 years time the death stats for lightning bolts will be similar and for road accidents will probably have declined. Which way do you think the terrorists stats will go?
The comparisons given are accidents and happen through negligence or plain bad luck.
Even so, terrorism may have cumulative political and social effects. People don't like to know there are others out there who wish them harm. Once a certain threshold of resentment is reached within an affected society then suddenly massive unrest could erupt.
Some politicians are trying to mitigate this by suggesting we should just get used to the occasional terrorist attack and treat it like a lightning strike or a piece of heavy furniture falling over.
Rather than thinking in terms of mortality rate over a period, its more accurate to think in terms of events. A single lightning bolt strike can at most affect 0 ~ 10 people with a gaussian distribution. A terrorist attack on the other hand has a long tail distribution and can cause 10^0 ~ 10^4 deaths.
There is no organized cult going around making lightening bolts with explicit intention of causing large scale harm. On the other hand there are several organized terrorist groups which are intentionally trying to do that. As far as being overweight or bad driving habits, billions of dollars are poured into health care system, automated driving and regulations with goal of reducing deaths due to them.
What?? What does legal driving age has to do with DHS budget? You are simply rambling, different mortality causes have different risk models.
Or to explain simply you are comparing "Apples to Oranges".
If your goal as a government is to minimise the number of lives lost that were preventable, then the argument is that there are many more effective ways of doing it other than spending huge amounts on security services.
I presume there's some stat somewhere that says that young drivers are more likely to be involved in fatal traffic accidents. No-one would claim that dying in these accidents is not tragic.
So if you were to raise the legal driving age by a year, you may end up saving lots of lives, and that would be a lot cheaper way of saving lives.
It's not a flawless argument, as one has to balance freedoms with restrictions and the fact that any historic analysis of attacks has to try and unpick the fact that security apparatus was in place in the past. Spending 0 money on security could have unforeseen consequences, and most people would accept that preparing and executing an attack would be easier.
Since "Terrorism" is a political problem, how about a political solution? Stop going into Muslim countries and murdering women/children and tearing down governments with no plan for rebuilding? Be more cautious about what you do on the world stage. Stop bombing brown people just because they don't support 'American interests' and such.