Did you have real arguments that had merit?
Because I've literally had a room mate openly interject in a Poetry class that was starting a month long unit on Dickinson "Emily Dickinson sucks, can't we focus on a better poet?"
The evil liberal professor was overjoyed that a student was talking in an otherwise morgue like 8 am poetry class.
"How so?"
"She's winy and self centered, I find her prose drab, but most of all I find that nothing we've read from inspires any greater understanding of life. Her art fails to motivate any emotion beyond the desire to close the book on her boring works."
"Well, those are legitimate grievances but what poet from the same time period would you prefer to focus on?"
"Tennyson. See, The Higher Pantheism"
"Tennyson is actually my favorite poet" replies the professor.
I don't know where you went to school but I've never seen a professor deny people speech unless it was out of format (ie 45 min lecture followed by 15 minute Q and A when that one student just keeps interupting the lecture section and can't wait for Q&A).
Every professor I've ever had in college practically danced a jig when a student challenged them academically. It was like the highlight of their week.
If you had one social sciences professor who had no interest in the science aspect, well there's a lot of imperfect people in the world.
Also, your above comment is literally written in the form of "that's your unreliable anecdote, I'm not going to post objective data so here is my anecdote without data points".
So here, have another anecdote.
Every professor I had in four years of undergrad and four years of graduate school LOVED students critically challenging the course material with scientific arguments.
I can comment a little bit on this. I dated a grad student in English for 5 years and took part in some of her academic activities, participated in her friend circle, etc. all in the same city where Lindsay Shepherd is having her issues.
I would say overall my experience was very similar to yours, however there's reason to believe that this state of affairs was set to change.
The key point has to do with the behaviour of the graduate students in different contexts. In my own undergraduate English courses, passionate disagreement was absolutely encouraged. In general professors and TAs at that level appreciate students who are actively engaged, BUT these students are not commonly at a level where their analysis of a text is informed enough to be truly compelling, so a true dissenting opinion from a lit crit perspective is just not going to happen. Now there are always a few cases where the breakthrough to the foundational assumptions does happen, but the TA is motivated to move past it quickly because (1) she can't spend the whole class in discussion with a single student, (2) she can't be questioning herself while simultaneously maintaining authority over the classroom, and (3) chances are the "dissenting" position of the current intellectual environment is not interesting to her anyway. To the dissenting student, it's understandable that this behaviour could seem like a cowardly dodge, though there are multiple converging reasons for it. In a lot of cases the little freedom-fighter is just an overconfident moron anyway.
Now switch to the graduate level class (I only attended a few of these, though I heard second-hand about almost all of them, so my perspective is limited). This particular program was very clique-y and very competitive. I imagine this is fairly generalizable since gainful Arts professorships are few and far between and grad programs tend to include a lot of quirky, high-intellect people who prefer to stick tightly together in small numbers. In this setting a student's criticism is expected to be fairly informed, and the easiest way to project an image of "informed" under extreme pressure is to take the instructor's (well-developed) position and add a bit of your own individuality to it and run with it. Developing a new position from scratch is much more work and contradiction with others puts you in a dangerous social position. Now you might counter that different students would take on the arguments of different professors, which would result in some diversity, but this wasn't the experience I observed. The old-guard (symbolized in this case, coincidentally, by the Tennyson prof) was
old and on its way out. Students of the new ideology put up with him to get their grades and moved the hell on. Anyone heard defending his positions elsewhere was teased and dismissed. I myself saw a few (white, male) students leave the program partly because they were no longer inspired by the direction their work was being pushed in and partly because the social consequences of resisting that direction made an already miserable experience even worse.
The TL
R is that Arts education can be great and receptive to truly diverse discussion, but in my experience graduate programs tend toward ideological bubbles by design and cannot be trusted to produce truthful or even broadly useful output. I think Peterson over-states his case when he projects to full-blown Marxism but I agree that I wouldn't want my own children to waste time and money or risk losing faith in their intellect in such an environment.