I'm strongly in the "humans are omnivores" corner. Last week I happened to be in the small town of Clovis, New Mexico where pre-historic human artifacts were discovered in 1929 and at the time were the oldest human finds in North and South America, dating to 11,500 years before present. Spearheads were found along with animal remains and I don't think the sharp pointy things were used to gather plants.
en.wikipedia.org/wiki/Clovis_cultureCultivated grains came many thousands of years later (wheat was cultivated in Europe long before grains such as maize/corn were grown in the Americas, thousands of year after Europe).
There is no doubt we humans are omnivores but is everything we eat good for us? Of course not.
I used to be a vegetarian and was fit and healthy. UC made my gut reject most food except meat and non-starchy veggies. I loved being a vegetarian but the gut rules.
Find out what makes your gut happy and eat it. (Silence of the Lambs being an exception).