i suspect that a huge factor in the defense of students using gen ai (and academic dishonesty in general tbh) comes from the fundamental misunderstanding of how school works.
to simplify thousands of educator's theories into the simplest terms, there are two types of stuff you're learning in school: content and skills. content is what we often think of as the material in school- spelling, times tables, names, dates, facts, etc.- whereas skills are usually more subtle. think phonics, mental math, reading comprehension, comparing and contrasting; though students do those things often, the how usually isn't deemed as important as the what.
this leads to a disconnect that's most obvious when students ask the infamous "when will we use this in the real world?" they have- often correctly- identified content that the content is niche, outdated, or not optimized but haven't considered the skills that this class/lesson/assignment will teach.
i can think of two shining examples from when i was a kid. one was in middle school when they announced that we were now gonna be studying latin, and we all wondered why on earth they would choose latin as our foreign language. every adult promised us it'd be helpful if we went into medicine, law, or religion (ignoring that most of us didn't want to go into medicine, law, or religion), but we didn't buy that and never took it seriously. the truth was that our new principal knew that learning languages gets harder as you get older, and so building the skills of learning a language while it was easy for us was more important than which language we learned, and that's an answer twelve year old me would've actually respected.
similarly, my geometry class all hated proofs. we couldn't think of a single situation where you'd have to convince someone a triangle was a triangle and "look at it, of course it's a triangle" wouldn't be an acceptable answer. it was actually the band director who pointed out that it wasn't literally about triangles; it was about being able to prove or disprove something, anything using facts.
and so, so, so many assignments that are annoying as hell in school make more sense when you think about the skills as well as the content. "why do i have to present information about something the teacher obviously already knows about?" because research, verifying sources, summarizing, and public speaking are all really important skills. "why does this have to be a group project?" because you will have to work with other people in your life, and learning how to be a team player (and deal with people who aren't) is an essential skill. "why do we have to read these scientific articles and learn about graphs?" because if you can understand them, people can't lie to you about them.
now, of course, there's a lot we could do better- especially we as in the american school system. the reason i have an education minor but am not teaching is because of those issues. there are plenty of assignments that are busywork and teachers that are assholes and ways that the system is failing us.
but that doesn't mean you should cut off your nose to spite your face!
the ability to learn and grow and think critically is one of our most powerful tools as people. our brains are capable of incredible things! however, the same way you can't lift a car unless you consistently lift and build up to that, your brain needs to train in order to do its best.
so yeah, maybe chatgpt can write a five paragraph essay for you on the differences between thomas jefferson and alexander hamilton's governing philosophies. and maybe it won't even fuck it up! congratulations, you got away with it. but by outright refusing to use your brain and practice these skills, who have you helped? you haven't learned anything. worse, you haven't even learned how to learn.