“There are federal laws about schools and their agents recording students as it relates to their education”

And there is no indication that the professor here planned to violate any of them.

“How do you think things like Flock came to be?”

Not from a benign study about better teaching methods, or of anything akin to it. Video is a rich data source. I hope researches get to use it more. I’m not selling all that out just because one completely unrelated private company misuses data.