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You did, though.
I understand that you said that poor teaching is inexcusable, and I think now that you have clarified the above we are mostly in agreement, though I do think that there is still a big difference between a student who attended all the lectures complaining that they didn’t learn anything and a student who didn’t attend anything complaining that they didn’t learn anything. If a student puts a reasonable effort (attending lectures, asking TAs for help sometimes, completing all the homework) into learning the material in a class and doesn’t feel like the professor put in their share of the effort into teaching the class, I think that’s its reasonable that they would complain about their learning for that class. Yes, no one in grad school or lab or whatever will care whether you “tried” to learn the material, only whether you actually did. But I’m not an employer or a PI, so I do care.</p>