A lot of animals in the wild stink. Seriously. Check out a farm or a zoo. It’s quite possible that people just used to generally smell bad before the modern age.

That's definitely something to consider, but when I really think about it I'm not sure I completely agree with this. I am sure that some animals smell more than others, but also that a lot of the smell you notice especially in zoos is because you're smelling their poop nearby. I think if you take most animals away from their bathroom area you may notice much less odor on their bodies.

I think of cats as an example, since I'm most familiar with having them at home. Cats are typically nearly odorless unless they have some health issue. They may not be the best example though, since they do clean themselves all the time unlike most other animals. Another thing to consider is how would those animals smell if they ate their natural diet that they would eat in the wild. I think that would also have an effect on their smell.

In short, I don't think there's much evidence that humans stunk to high heaven before the invention of soap and deodorant. I would gladly consider the evidence though.