I think people should understand that the place they're going to isn't an art school the way you think it is.
It's a college prep school.
It's a place where they teach you less about how to draw and more about how to develop work that could get you into your university of choice. Think of it as mock exams for art students, if you fail that "exam" they'll let you know at the critique. Yatomi Painting Class, where both Inuyama and Toyoda came from is an actual art class where they teach techniques and fundamentals. Prep school are more advanced and starts diving into intent and expression. Prep school instructors will tell you what you are lacking, in Inuyama's case it's that his art is bland.
Teachers at prep schools are very harsh because their schools have reputations to uphold, usually on their pamphlets they would list a percentage of successful college entrants from their school. If you're not at a level where they think you might even stand a chance, they would much rather you not come at all and give that spot up to someone else more talented/hard-working. You're paying them to guide you and they're betting on you to deliver.
The teacher is harsh but right, she's not shitting on his work and she even said his composition is fine and details are clear. But she is saying that his work is not up to par for something that could get into college. It's better to weed out people who are phoning it in, save their money, save the teacher's time, and save the opportunity for someone else.
Admittedly she said she's assuming Inuyama is a slacker, but she doesn't know how hard he tries.
On a side note, one way to remedy boring still life is to increase contrast when rendering the objects. If everything is too clean and perfect then it's really not visually striking. One way Inuyama could improve is actually to render only a specific object in clear detail while leaving others more loose (but still accurate). This bias injected into the work tells the viewer what the artist is interested in and what they consider the star of the composition, hence "intention" and "meaning".