Many years ago I needed a face database for some AI work. Everything I could find for free was crap and it wasn't worth the price to pay for any of the better ones. For a few weeks I took a two hour lunch in the tourist area of town at the busiest fast food place. I parked right by the sidewalk and had a camcorder record HD from my car. I filtered out people who didn't look at the camera or who's face was partially covered. Lighting was consistent because it was always recorded at the same time of day. I probably had 5-10k faces of usable quality though I never tried training with the full data set. A few of the other grad students in my lab asked to use it when they found out about it. As far as I know my filtered version of that database is still floating around at the university.

In short, there is way more data than can even be identified floating around. That being said, the Facebook dataset is likely a treasure trove of interesting stuff. I can't imagine what deep learning on millions of pictures with their associated metadata could figure out. It's sad that data isn't being used for good.