Then again, perhaps you are just a well trained markov chain, and not actually a person.
That's an overstatement. All you can really conclude is that science cannot say whether or not any non-humans are sentient.
I agree that human characteristics are sometimes falsely assigned to animals. But that doesn't mean that human characteristics can only ever exist in humans. If a crow exhibits theory of mind, it just suggests that humans are not as unusual as previously thought. It does not mean that we are assigning the full philosophical implications of human sentience to that animal. In fact science could not possibly do that and still be science.
Infants are known to lack forward-planning, object permanence, and many many other indications of reasoning. I don't think it'd be wrong to say that they behave quite like little finite state machines.
Human crying as any strenous activity generates heat.
This is not evidence that the crying act was just to generate heat. Not that it's evidence that they missed their mom, but it's neither evidence for the heat theory.
You can comfort a crying child with a blanket; maybe all human distress is just a need for a blankie?
A common example of anthropomorphism is in voles (and other rodents). [1,2] Very long ago, scientists noticed that bank vole pups frequently cry when their mother leaves the nest. The scientists assumed that the pups were afraid, and missed their parent. Eventually, it was discovered that the absence of their mother drops the temperature of the underground nest, and that the pups cries are actually a mechanism to generate heat. When scientists took their mother away, but increased the heat of their den to normal levels, the pups did not cry. The animals were not communicating or displaying anything resembling "human" emotion, but were innately responding to environmental stress.
No matter how much we want to believe that animals are sentient, have emotions, and communicate to each other via language, science indicates that's just not the case. In fact, there have been numerous studies that indicate anthropomorphism is a byproduct of our complex social structure.
Nice job bringing racism into a discussion about dolphin vocalizations, by the way.