Evolutionary biology has been trying to shed teleology ever since Darwin, and is apparently still failing judging from popular notions about evolution.
There is such a thing as convergent evolution. A fish, a dolphin, a shark, and an ichthyosaur all look very similar on casual inspection. But these animals are already very closely related, all being in the same phylum.
What non-vertebrates have evolved to look the same? The closest convergence from a non-vertebrate would probably be a squid…it has a similar shape…if the tentacles are tucked up. And of course the squid swims by water jets rather than wiggling it’s tail, which it doesn’t have. And on and on. A squid is a fast swimming pelagic predator like a dolphin, but it isn’t much like a dolphin despite sharing the exact same environment.
If a creature that is similar to a human is likely to evolve on another planet, then just about every species on earth would be likely to evolve. Why would something resembling humans be likely, but not golden bamboo lemurs, or kangaroos, or narwhals, or pandas, or naked mole-rats, or giraffes, or ostriches?
When you consider the evolutionary history of Homo sapiens, you realize what a long strange trip it’s been since the primordial ooze. We were once single-cell protozoans, then colonies, then wormy things, then fish, then amphibian-y creatures, then mammal-like reptiles, then little mousy things, then tree-climbing little mousy-things, then monkeys, then tail-less monkeys, then ground-dwelling tail-less bipedal apes. It’s easy to imagine that if one saber-tooth tiger had killed one too many of our ancestors, humans would never have evolved, we’d be extinct. And it is many times more likely for a human-like creature to re-evolve via convergent evolution here on Earth than on some other planet, even if millions of planets have complex life.
Think about bipedalism. There have been hundreds of bipedal organisms in the history of our planet, but NONE of them looked much like a human. There have been lots of large brained creatures in the history of our planet, but none of them were much like humans, except for our ancestors and sister species. An intelligent alien is just as likely to resemble a squid or an elephant or a dinosaur as it is to be a hairless bipedal ground-dwelling but former-tree-climbing ape. Which is, not very likely at all. It’s likely to resemble NOTHING ON EARTH.
And that’s not even getting into the biochemical issues. All life on earth is related, and has the same basic biochemical machinery…DNA coding for RNA, ribosomes that create protein from RNA, only 20 amino acids out of the thousands possible, phospholipid bilayer cell membranes, and on and on. We have no idea how much of this machinery is required for life, and how much is simply due to how the first living thing arose on earth. But it’s pretty likely that any alien life would have a radically different biochemistry from earth life.