Yes it doesn't seem right to say that just because they're using stones and twigs that they're on their way to building civilization.

Fire was the major milestone for humans. If chimpanzees start using fire, that's when it might be time to worry about them going all Planet of The Apes on us.

But even that's not a perfect metric on its own, because some birds [apparently make use of fire](https://www.sciencealert.com/birds-intentionally-set-prey-ablaze-rewriting-history-fire-use-firehawk-raptors).

The difference would be if some chimps knew how to create fires, teach others, use it to cook food, get better nutrition from it, their physiology starts changing so they get smaller guts and bigger brains, then they've got the cognitive ability to be serious threats to humans and start questioning our place on the food web. Just using tools isn't enough.