If life has been discounted, then life has not been valued. There seems to be a persistent belief that economists somehow decide the value of things.
Economists try to measure the value people put on things.
Perhaps a simple way to think about an economic valuation as a public opinion excercise, where public opinion is measured by looking at what people actually choose to do. Blaming an economist for the value that comes out of an economic study is like blaming a pollster for the results of a public opinion pole, or for a physical example, blaming a geologist for the weight of a rock, or a physicist for the mass of an electron. In all cases, these people are using the tools of their discipline to measure the phenomena of interest. It is very valid to criticise the methodology - if a pollster does not ask the 'right' question, then the answer will be invalid. Likewise, if the economist's method of measuring what people value is incomplete, then the result will not be accurate.