Jumping spiders are smarter
Bees' intelligence relies on them being a hive organism.
Aristotle used the word "insects" for all terrestrial arthropods and this was followed for millennia until the last two centuries when someone preferred to use "Insecta" instead of "Hexapoda", without giving any reason for this, and others followed this taxonomy.
Even so, the exact extent of the term "insects" varies between biologists, because some do not include all wingless hexapods under "insects".
In an informal discussion, I do not see any mistake in using the word "insects" with its original meaning from Aristotle, which is also the meaning that can be encountered in a lot of old books. For unambiguous animal classification, the word "hexapods" is preferable.
So in this case, it matters that spiders are not in fact insects in the strict sense.
Quote from above:
> they are by a healthy margin the most intelligent arthropod
This is one of those very rare cases in which "entomology" or "etymology" might have been chosen without the intended meaning being clear. :)