I have done precisely that type of thing dozens of times in the last 10 years, and it would have never occurred to me that I was doing anything wrong. And yes, I always had to login first through a browser, figure out how the hell the cookie was stored, export it into a format that curl liked, figure out the URLs for all the docs, etc, etc...
And yes - when I was younger and more energetic, sticking my laptop in unlocked cabinet with an open ethernet port is exactly the sort of thing I would have done, without for a second believing I was doing anything "criminal".
I have to believe that MIT has hundreds (thousands?) of these types of webscraping events occurring all the time.
What made this one different from their perspective?