e.g. Earth is the only place where life could have formed. We have yet to set foot on even 1 another planet but we are pretty sure we are alone in the entire damn Universe.
This is an incredible misunderstanding of the Anthropic principle. It has nothing to do with god, it does not suggest that life could only exist on Earth, and it does not suggest that we are alone in the universe.
If anything it's an argument against Intelligent Design. E.g. life is the statistical result of a vast universe (or multiverse) of permutations - some of which are not conducive to life, and some of which are. And when life looks out and says "wow it's uncanny how perfect this place is, there must be a divine hand at work" - it's only observational bias that makes it appear that way. Because life could only exist to make such observations in regions of the universe which are suitable for life.
But on the other hand it also prevents one from saying "we exist, therefore intelligent life must be commonplace".
> we are pretty sure we are alone in the entire damn Universe.
We absolutely are not sure of that in any way, shape or form. Quite the opposite, given our knowledge of the universe and conditions necessary for life forming, it's highly unlikely we're alone. There's a reason that we call a paradox the fact that we haven't found any extraterrestrial life yet: the Fermi Paradox.
Anyway, the anthropic principle says nothing about that.
If anything it's an argument against Intelligent Design. E.g. life is the statistical result of a vast universe (or multiverse) of permutations - some of which are not conducive to life, and some of which are. And when life looks out and says "wow it's uncanny how perfect this place is, there must be a divine hand at work" - it's only observational bias that makes it appear that way. Because life could only exist to make such observations in regions of the universe which are suitable for life.
But on the other hand it also prevents one from saying "we exist, therefore intelligent life must be commonplace".