There doesn't seem to be much consensus on defining what intelligence is. For the definitions of at least some reasonable people of sound mind, I think it is defensible to call them intelligent, even if I don't necessarily agree. I sometimes call them "intelligent" because many of the things they do seem to me like they should require intelligence.
That said, to whatever extent they're intelligent or not, by almost any definition of intelligence, I don't think they're achieving it through the same mechanism that humans do. That is my main argument. I thing confident arguments that "LLMs think just like humans" are very bad, given that we clearly don't understand how humans achieve intelligence and the vastly different substrates and constraints that humans and LLMs are working with.