alt Hacker NewsA very important fact to remember is that brains are not a requirement for intelligence (in the very broadest sense, not the more specific one used here), nor even neurons. All cells have some amount of computational power and can meaningfully react to their environment; a common example is white blood cells quickly adapting to pathogens to try to destroy them. Networks of cells are even more powerful, such as slime mould exploring the space around it until it detects nutrients and then channeling all resources in the direction of such nutrients. Plant roots have sophisticated sensory abilities detecting numerous kinds of chemicals in the soil, and actively search for nutrients and avoid contaminants. Even jellyfish, some of the simplest animals, long thought to be essentially passive, in fact detect and actively steer themselves towards prey.
Intelligence actually exists at all levels of life, and brains are just an apex of achievement, just like eyes are an apex achievement of light-sensing mechanisms that similarly exist all around the tree of life.
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Additionally, both plants and slime mold have been shown to be capable of keeping track of time elapsed in experiments, it’s so cool and bewildering (how this is done as it seems quantitatively different from other automaton like behavior that could be programmed so to speak from a layman’s perspective at least).
Superstitious humans never really gave up their believe system that we have souls. Sure, we expanded it to include non-humans, and sure, the age of science compelled people to give it a more secular label ("neurons"), but we're as superstitious as ever. We have entire quasi-religions out there masquerading as lifestyles and "just common sense", and they all rely on the neuron being special.
So it doesn't really matter that technically you are correct.
I understand what you're saying but it sounds like you know what it means to separately ask about animal intelligence in the sense relevant for evaluating, say, crows vs pidgeons, and that question obviously is not just about animals having sophisticated immune responses.
I would venture a guess that nearly all animals will turn out "intelligent" if all we really mean is they things like complex immune responses to disease, or complex coordination needed to grow an embryo. Those matter and raise profound questions about how incredible natural selection can be, but I would wait for an actual sin of commission before treating any commentary on animal intelligence like it neglects to appreciate sophisticated behavior of cells.