Earlier quoted context omitted.
> the professor was there to set the curriculum and force you to study (things that otherwise you didn't know were important or didn't want to pick on your own That's what it means to NOT be self-taught. That you got an organized overview of a subject in a systematic manner. What was the expectation otherwise? That somehow another person instilled all your knowledge directly into your brain?
> What was the expectation otherwise? That somehow another person instilled all your knowledge directly into your brain? Perhaps close instruction and observation and correction? More like an apprenticeship, or the way your parents may have taught you how to ride a bike or use utensils etc etc, which differs markedly from a professor speaking to a large group and leaving the struggle and attempt to master a subject t…
You have lectures (with questions and discussion), labs, assignments and corrections, and so on. Obviously the lectures and such are not one on one, but given to the class you're in. It would be expensive and require dozens of different professors just for one person to cover all study subjects with a degree.
Also a lot of it concerns learning about stuff you were pointed to by reading the relevant material, so it's can't be done similarly to the one to one teaching a tacticle thing, like how to handle glass blowing to get into the guild, or how to ride a bike.
Still, regardless of what it contains, the difference between self-studying or not is that in the latter you are given a systematic, organized, curriculum to follow.
And it's the quite common idiosyncratic mix-and-match, and jumping from subject to subject, and often lacking foundational knowledge in base areas, that academics look down on those who "self-studied".
Or course if someone studied by themselves in an equally systematic and organized way as a university curriculum, coverting the same bases and expanding in a similar way, they'd not really be "self-studied" in the spirit of the term, just nominally.
But traditionally that was hard or impossible - and in any case, very rare (the other kind of haphazard self-studied person was far more common). Now with the internet and easy access to information, it's somewhat easier, what you need is heavy discipline.