Bringing a child into this world must feel like utter terror. Since you care about this tiny human so much and just want the best for them, I could imagine that any critique of your child - whether valid or not, could feel like an attack. Teachers know this firsthand, as they're saddled with the difficulty of telling parents about the rate of their children's progress.
The Reddit user FourLear11 recently shared a story of a mother who simply couldn't wrap her head around the idea of her child having a learning disability. For this specific mother, it was a matter of pure ego.
Rather than accepting the news and figuring out how to best help her child learn, she lashed out at the teacher and claimed it was impossible for her kid to have learning disabilities since she has a Phd. There are truly too endless layers of bad parenting to unpack here, luckily, the teacher wasn't taking any BS.