I was able to display the map and link all of the buttons to actions using JQuery. In fact, the navigation toolbar also works because the zoom to full extent, previous extent, and next extent buttons are working. It seems to me like anything that relies on the "activate" function is not working.
At first, I thought it was my code, so I started looking at the sample, that can be found here Navigation toolbar. The same thing happens! The Zoom In, Zoom Out, and Pan buttons aren't working (the ones in the Navigation toolbar). I figured it was my browser (Chrome on Mac), so I tried Safari, then I tried Firefox. No difference. Some threads that it was a device thing so I tried another computer (also Chrome on Mac) and no change. Finally, I tried it from my phone (Chrome on Android) aaaand the Zoom In and Zoom Out buttons in the Navigation Toolbar are still doing nothing.
I'm not crazy, right? Something IS wrong with it! After all, I AM using the official sample provided by Esri to test!!
Thanks for your help.