Junk food

As a snack, roasted maize isn't bad (low calories, high fiber) - but you probably knew that.

The real problems are either eating boatloads of the stuff drowned in salt, sugar, and/or fat, in Modern Fat Westerner (MFW) style, or making it too large a part of the regular diet. The latter probably contributed to the fall of Cahokia, for example. (Cahokia, near what's now St Louis, was a major Mississippian settlement; in the 13th century its population was comparable to that of London.)

As for the pine-cone shape of Exhibit B - that's a pretty common cob shape for maize varieties that existed prior to modern farming. There are similar ones on the cover of the book "Indian Corn of the Americas", for example. You can buy cobs like that around here (Michigan) in the summer, at farmers' markets and such.

Teosinte, on the other hand, is very different from maize (morphologically; genetically they're pretty close, though cross-fertility is limited). Apparently the ancient Mexicans bred a *lot* of generations of selected teosinte strands to arrive at maize. And maize has to be domesticated - it generally can't reproduce in the wild, because the kernels don't separate from the cob on their own.