Paleo-anthropologists put the controlled use of fire (not necessarily cooking) at somewhere between 400 to 800 thousand years ago. Richard Wrangham makes the case that cooking is what changed us from Homo Habilis to Homo Erectus - roughly 2 mya. In any case, hominids ate stuff raw for at least 500,000 years and maybe longer. That's both meat and veg.

Who says you can't eat meat raw? Personally, I don't. I like my meat cooked. I like my veggies cooked too. The idea that its paleo if it can be eaten raw is just a simple rule - probably too simple. Also, cooking meat or tubers in a fire is pretty simple. Soaking beans and boiling them is much more complicated and came way, way later (requires pots at least - bronze age?).

Paleo is a context for discovering what is healthy. We also use science here. For example, honey is a paleolithic food - but not necessarily healthy. Heavy cream and butter/ghee are neolithic inventions, but many here find them to be very healthy. Nuts are paleo, but high in n6 - so most tend to eat them in moderation (or not at all). Dark chocolate and coffee are not paleo - but a lot of people here indulge in them as well.

Raw versus cooked is an easy way to think about it when you are first starting out, but in the end its probably not that useful of a heuristic.

There is actually a whole subset of paleo folks who mostly or only eat raw meat and veggies. (website and forum). In fact, the first person I ever met who used the words paleolithic and diet in the same sentence back in the late 90's only ate raw meat and nuts. I haven't really read or thought enough about it to form an opinion beyond if it works for them than that's fine and I see no reason it couldn't be healthy if done right. I fear for me it would lead to not eating very much, orthexic tendencies, reduced social interaction and getting annoyed with fellow followers using psuedo-science to justify a lot of their choices. Those were all the reasons that I stopped being vegan and started eating paleo in the first place.

Raw is what animals have to do.

Cooking made us human.

The ability to make nutrients and calories more bioavailable made us able to develop the brains that make us rulers of the planet today.

Heres a great read: Catching Fire: How Cooking Made us Human

Many veggies taste better cooked. The sugars are more concentrated making the veggie less bitter. Cooking also breaks down the fibers making a veggie easier to eat. I eat carrots mostly raw, but I can eat more of them if they were cooked. Something like broccoli to me tastes MUCH better cooked (especially roasted) than it does raw. Fruit of course is better raw.

All meat can be eaten raw. The heuristic is about digestion, not whether or not a bacteria or parasite could be present, which is true of any food, plant or animal. However, there are plants that will not digest without cooking or other processing. These are generally not considered paleo foods.