How Hot Is Habitable?

Unresolved: The bulk of the science community, flooded with taxpayer cash for any study or activity remotely related to global warming/climate change/climate disruption/carbon pollution (the name is in flux), generally predict disaster for humanity if our planet's average temperature varies by fractions or a few degrees in the course of a century.

Astrophysicists, searching for and finding exoplanets in the "Goldilocks Zone," worlds unfathomably far away but believed to be just massive enough and just distant enough from their suns to be within a range that could support life, don't parse out habitability to fractions of a degree. Is human life so fragile that our Goldilocks Zone is vanishingly small, but worlds elsewhere can be declared habitable from thousands of light years away?

Should the alarmism infecting the new field of "climate science" apply to analysis of distant planets too? Or does it have anything to do with keeping funding flowing, changing our lifestyles to pre-ordained standards described by people with low esteem for American values, as so many people claim—who are then ridiculed and dismissed as deniers by people in white jackets?