We all agree it would be bad to die at 40 if you could have lived to 60. By that logic, isn't it bad to die at 80 when you could have lived to 100? If you could do something to increase that probability, wouldn't that be a good thing? Good health also increases quality of life, independent of whether it extends lifespan.

To put it another way, pre-civilization life expectancy was somewhere around 30 years. Would it have been wise to say to someone who was trying to live to 60, "So what? We all knew we're going to die from the age of five or so. This is pointless."

I agree that sometimes these health protocols are excessive, and can be driven by fear of death, among other things. It's also uncertain how many years on average any given habit will add, and there are opportunity costs that need to be factored in. At the same time, I see this common knee-jerk response to dismiss any attempt to extend human life. Given the abysmal state of health of the average person, I think it's a good thing that some people are working on figuring out what contributes to optimal health.