We currently have multiple in captivity that can understand and sign basic English, going as far as having basic conversations with their keepers ("How are you", "What would you like to eat", "Why are you sad", etc.).

They were taught that by their handlers. Their basic intellect isn't even on the level of human child, it's just adjusted to the circumstances they're living in. Captivity isn't dangerous, so they can spend less time worrying about predators and food, and more on wondering what the fuck is that creature saying. It's not like they spontaneously understood English, they just recognized the "tells". Wild chimps use different shouts to communicate - "Watch out, predator!", "I wanna play!", "Fuck off, that's mine.", "New Air Jordans are here!".

I think one of other main reasons many people are so ignorant about evolution and apes in general is because they like to think humanity is special and that they are better than other organisms on this world, while over the last decades we've discovered that's absolutely not the case.

But we are special. None of other species on Earth is as intelligent, as resourceful, as vicious as us. That doesn't necessarily mean we should deny what we evolved from. It's just that most mono- and polytheistic religions have bit in their holy books about human being made as an image of creator, and take it very literally. That excludes man having any ancestors. You can recognize a good religion by it not being focused on where and how we came from, and instead on ways to live (and I don't mean "don't wank on sundays", "treat goyim like shite", or "behead infidels" - more like "don't be dicks to each other").

Now that I think of it, religion is a result of evolution - at some point humanity turned from wondering why inserting things into one's anus is fun, and focused on oppressing women! That's a progress.