Maybe this is a better question for AskCulinary. If so, I apologize.
It seems like the process for making chocolate bars is a huge pain in the ass, and it's extremely counterintuitive. So you harvest these cocoa beans (which has to be done by HAND, because they don't all ripen at once). You shell them. You ferment them for about a week. You dry them. You roast them until you get to a desired flavor, then crack them to separate the "nib" from the rest of the chaff. The beans are then ground, sometimes pressed to separate some portion of the cocoa butter from the solids, and then "conched" for days to weeks in order to get the desired texture, then combined with other ingredients (such as milk, butter, or at the VERY LEAST sugar) in order to make it palatable. Then you have a bar.
Or at least the process is something like that -- it just seems like an awful lot of work for what must have looked to early explorers like a dumb, bitter bean growing on some kind of tree and doesn't even have the same caffeine content as coffee. Why did we bother?
You´re making the bold assumption that without such processing, cacao is not palatable. I will argue that this is entirely wrong. You may find this post on the significance of chocolate in the Maya world interesting, particularly this response:
Acquired taste is probably the best term. Maya cacao is to black iced coffee as smooth Dutch milk chocolate is to a Starbucks Pumpkin Spice Latte. Plain, it's a somewhat bitter drink from beans that has a certain cultural niche and conisseurship, but a lot of the world has tried a few times and been utterly turned off. Add some milk and sugar, and the appeal broadly widens. Some people will say you can try some plain cocoa powder to get a good impression, but that's akin to eating a scoop of espresso grounds. Also remember that they had fruit juice and sweet corn drinks that may have been mixed in.