You might not have a school education, but you have educated yourself. It is unfortunately common to hear people complain that the theory one learns in school (or by determined self-study) is useless, which I think is what the geybeard comment you replied to intends to say.
OK, the real differences between self directed study, and school based study:
1. School based is supposed to cover all the basics, self directed you have to know what the basics are, or find out, and then cover them.
2. School based study the teachers/lecturers are supposed to have checked all the available text on the subject and then share the best with the students (the teachers are the ones that ensure nobody goes down unproductive rabbitholes)
3. People can see from the qualifications that a person has met a certain standard, understands the subject, has got the knowledge, and can communicate that to a proscribed level.
Personal note, I have done both in different careers, and being "self taught" I realised that whilst I definitely knew more about one topic in the field than qualified individuals, I never knew what the complete set of study for the field was (i never knew how much they really knew, so could never fill the gaps I had)
In CS I gained my qualification in 2010, when i went to find work a lot of places were placing emphasis on self taught people who were deemed to be more creative, or more motivated, etc. When I did work with these individuals, without fail they were missing basic understanding of fundamentals, like data structures, well known algorithms, and so on.
