It isn't even necessarily bad for humans. Most of us have some values which we cherish more than our own lives. If nothing else, most people would die to save everyone else on the planet.
On the other hand, although there are things worth dying for, we'd usually prefer not to have to die for them in the first place.
Terminal values and preferences are not rational or irrational. They simply are your preferences. I want a pizza. If I get a pizza, that won't make me consent to get shot. I still want a pizza. There are a virtually infinite number of me that DO have a pizza. I still want a pizza. The pizza from a certain point of view won't exist, and neither will I, by the time I get to eat some of it. I still want a pizza, damn it.
Of course, if you think all of that is irrational, then by all means don't order the pizza. More for me."