Most beans have proteins in them called lectins which are toxic unless neutralized via heat. I think this is one of the reasons most beans suggest a soak prior to cooking too, to help get rid of some of them. Some beans like lentils are pretty low in lectins though so it's not ALL beans. Kidney beans have a shitload of lectins in them. Also lectins can vary in how toxic they are, since ricin is a lectin and I'm pretty sure it's more toxic than what's found in kidney beans.

Lectin poisoning is pretty uncommon though because if you don't cook your beans they'll also be pretty unpalatable.

But yeah, that's why it's theoretically safer to eat raw meat, yeah it might have bacteria and stuff in it and it's gross as hell but raw beans are generally literally toxic