It’s fine to say solve this problem using the following tools, but not great to say “if you find another approach, I assume cheating.”
Students are human. Many have been taught to focus on one end goal: a grade. They see a mythical program that knows 6000x more than is taught in this 200 level course; of course they want to use it!
This was definitely a problem in classes before AI. I had a number of infuriating teachers who insisted on failing me for doing X, because "you're going too fast and we haven't gotten to X technique yet."
That said, having to do the introduction to programming class at uni despite programming for like a decade in high school was the bigger annoyance.
While there are certainly a handful of experienced students that use these things, ten years+ of experience shows that most are copying from elsewhere. A simple, brief meeting with the student is easy enough to ascertain that, however. And that was certainly a part of the process.
Regardless, that alone would not have triggered an academic integrity investigation and, again, there was no prohibition here.
As a student, _especially_ in the weedout classes where your performance in those classes decided if you could get into that major (I went to a school where you applied to majors 1-2 years after starting) it was incredibly frustrating to see other students cheating. When applying to a major that was well past capacity and very competitive to get into, it very much felt like a 0-sum scenario where cheating students were screwing the rest of us over. How awful would it have been to be declined from your major and have your career path severely impacted because so many students were cheating with 0 consequences
It was even worse when professors were notified but couldn't do anything about it (for example, a student next to me in an exam kept pulling out his phone but hiding it when the professor was nearby. I even notified her during the exam but she wasn't able to catch him so as far as I know, it never went anywhere.)
Similarly, I was a grader for a 300 level math class where about 50% of the class had blatantly cheated on an assignement (the solution manual on chegg had mixed up the questions so anyone who actually read the problem would've caught it because it was the wrong problem). I notified the professor and he said he would mention it in class but no other consequences occurred - they didn't even get 0s on the assignment!
All of your thought processes were very reasonable and I thought the best slide was comparing exam scores by people using LLMs on assignments vs people not using LLMs on assignments. I truly think that will convince people who otherwise might be borderline failing and desperate to pass that using an LLM is not in their own best interest.
I'd be curious to see (both as myself, and I think it'd be very convincing as a student in your class) the overall class grades for people using LLMs vs not. I could see someone reasoning "ok well if I get 100% on the assignment and scrape by on the exams, that still gives me a better grade than doing badly on the assignments (without an LLM) and doing slightly better on the exam"
Edit: I always thought for some reason that cheater would get their karma in their own way but in the real world, there are no consequences. I'm plagued by ads for ai-assisted ways to cheat on interviews every time I login to Blind. It actively is making things worse for the rest of us
The AI stuff aside, this comes across as a professor who feels threatened when his course isn't taken as doctrine. Being called a cheater for using external resources is ridiculous to me.