Am I right to be frustrated that my professor does not actually teach? This is a 101 philosophy class in an online format. Each week we have over 100 dense pages of a textbook to read as our sole source of information for the class. The teacher does not do any teaching and relies on the textbook.
Obviously a textbook is beneficial but especially for a 101 class, it is difficult to grasp these complex ideas without the input from your professor. Is this wrong? I am having a hard time understanding concepts and actually learning. No lectures or actual teaching. There are no actual in-class sessions: the work is posted at the beginning of the week and we submit by the end. Other classes I take in this format have provided lectures but this one does not. He only grades the work we did. Being paid to provide no expertise and guidance, only grade?
The assignments are discussions and quiz questions based on chapters in the text, that have to be usually 750 words or more. When he grades them he sometimes comments and says &quot;yes that is true&quot;. It is one discussion with usually 2 open ended questions and 2 quiz questions that are long open ended each week.
Further remarks following the comments:

Typically, discussions for this class are not beneficial because most people don't actually engage and debate/ go back and forth. We do not have discussion it is solely our interpretation of the readings. Most just say &quot;I agree with what you said and I like this part..&quot;. So it is not actually helping us learn and debate. But I cannot blame my classmates because the discussion we have to post are over 750 words so why would they want to read something similar to what they wrote. They can only do so much, they are not doing anything in this case except for grading which is frustrating to me.
There is only 21 people in the class. Obviously that is a lot of grading to do but he assigned it and could set the word count to be lower if he chose to. Most teachers reuse the same assignments and discussion questions each year or get them from the textbook. Every module/unit has been posted since September, so he is not lesson planning each week. He only has to grade each week, I am not denying that is a lot of reading but can you understand that it is frustrating for a student to not receive any actual instruction, but I am still spending a lot of money to take the course?
If I understand correctly, the professor has:

assigned readings
facilitated online discussions
given written assignments and quizzes, and graded them

But:

the professor does not himself participate in any activities (lectures or discussion)
the online discussion format does not lead to many useful interactions with peers
the professor gives only superficial feedback to written assignments

This does seem like poor practice. You are attending university partially to gain from the professor's expertise, rather than just reading books and discussing with peers. This is a class, not a book club. I acknowledge that there is a legitimate teaching style that involves activities, discussion, group work, and/or individual interactions rather than lecturing. But if your professor is as hands-off as you describe, I do not believe he is using this method, or at least not effectively. At a minimum, I submit that he should provide more detailed feedback (even at the cost of grading fewer assignments) and post a few comments in the discussion board to raise the level of the debate.
Despite this, I doubt there is much you can do. The professor did curate a course for you, facilitated group discussions, and is grading several pages per student per week (which may be a significant time investment). So unfortunately, I doubt that complaining to the department would lead to significant changes, at least in the short term.