I'm not equating dying to protect life with dying to avoid taxes. The first point was, it can be seen as reasonable to die to help your children. The second point is my stipulation that to say it's only ever reasonable in the case that your children are in mortal danger is silly.

If you value your life very low (for example, you are bedridden in the hospital, terminally ill, on the verge of death and will be in excruciating pain for the rest of your short life) and the well-being of your children very high, why is that so crazy? Soldiers in a country being invaded can go to war and die to protect their families from enslavement, rape, pillaging, and so forth, not just from death, and no one (well, usually) criticizes and demeans them for that. Are soldiers the only ones allowed to do that?

I can sense you're balking at the part money plays in the equation, and you do not like when money is assigned value beyond pieces of paper. Consider that the people making these decisions are likely not thinking of the dollar amount of the inheritance. I would bet they are thinking of the amount of good (whether getting lots of money = good can be debated, but let's assume it does, or at least assume they believe it does) they can do for their children when they pass. Being taxed on that money means giving up a lot of that good.