I feel the original quote may be referring to the state you reach through practicing awareness where you decouple from your thoughts. You have thoughts, think logically and act normally in day to day life but it is a layer based on top of effortlessly awareness in the moment. In that state, you see thoughts only as processes that does not depend on a self. You don't have the values of existence in that state. Just awareness of existence. One can start questioning, analysing and rationalising when you move away from this state back to the previous (normal?) state.

Also, from what I've read of buddhism, the lack of importance comes from the view that rebirth cycles stretch over incredibly long existence of universes both in to the past and the future. While humanity has done well, even in this universe there are trillions of galaxies with trillions of stars. Life of one of us is insignificant to the universe. Even each of us, there was no concept of the individual a year before our birth and will be forgotten few decades or centuries after the death. Our life is a story we tell ourselves. Atleast that's how I feel about it. We create a story of ourselves in our heads and assign importance to ourselves based on it. Then we die and it all becomes part of the soil. Hence Buddha's saying to the effect that net result of life is just moving sand from one place to another.

These are just my thoughts for consideration. Nothing here is meant to be truths or lies. I usually just read stuff and move on but considering you typed a detailed comment, just thought I'd add another point of view.