That's just blatantly incorrect.

Humanity believes that it has the ability to estimate the intelligence of other animals.

And the way that it does so is always by measuring how well the other species imitate human behaviors.

It doesn't take into account whether those other animals care to imitate human behavior or whether they know they're imitating human behavior or whether they want to imitate human behavior. And it most certainly doesn't understand how well those other animals' intelligence applies within their own niches. You can't test animals' intelligence by testing how closely they behave to human beings when operating mimicking human niches and human goals.

Speaking as someone who's autistic, I've done the research on that. In autistic people, there seem to be a higher number of certain specific neanderthal genes. I'm also very gifted, and work in STEM.

Neurotypical human beings are BLOODY TERRIBLE at recognizing any type of intelligence that is different than neurotypical human beings. It is ASTOUNDING how bad they are at it.

Neurotypical people can't even recognize the intelligence of autistic people. And good luck determining our goals. Other people think I am stupid when they first interact with me, but that couldn't be farther from the truth. I'll just say that revealing too much here would reveal my identity, and I'm not going to do that, but I have a list of accomplishments that I literally couldn't imagine most neurotypical people accomplishing, and I know many other autistic people who are very intelligent. Does this discount neurotypical intelligence? No, not in the least, and it's not intended to. But it does demonstrate that Fermi's Law could be nothing more than humanity's inability to identify other forms of intelligence. And hell, whether you even consider autistic people to be a different kind of intelligence, that's not even referencing animals.

What neurotypical humanity HAS developed is not the only civilization, but the only widespread manipulation of the environment in ways that significantly distorted the environment in such a way that their presence was undeniable long after an absence. That's not the same thing.