I don’t know. but they wrongly assume that conditions would have to be earth like for life to live.
I call BS on that.
They would only have to be earth like for US to live there.
The assumption comes from the thought that the universe is universal in the physical, chemical and biological laws that govern life.
Meaning that the general laws that allow life here, must also be applicable elsewhere for life to exist elsewhere.
But it’s not expected that life elsewhere is exactly earthlike, but that there’s a relatively narrow range. For example, life on another planet could have to live with gravity being 3 times what we experience, but it’s probably safe to assume that life couldn’t exist on a particular planet if it tried to exist on a planet with 500 times earth’s gravity.