The biggest bullshit with Adultism is basically that the people will defend it with: "Well, if we did not force X on kids, kids would not do it, because they hate X."
And then you actually look onto the research.
Kids do not generally hate learning or school. Quite the opposite. Children tend to enjoy learning and are naturally curious. It is exactly the fact that they are forced into school and into the rigid structure of it that often punishes curiosity but also is hostile towards the differences inherent in people, that kids hate it.
Kids do not naturally hate medical care. While medical care is scary at times, the fear usually comes from medical care scenarios being defined by adults overriding a child's agency, not explaining things to him, and otherwise being abusive, that makes children afraid of medical procedures. Additionally the way a lot of medical procedures go hand in hand with denying a child's reality ("Look, it is not that bad") tends to be traumatizing to children.
There have been studies done in this. If you explain a child - even a toddler - what you do and why, children will generally be a lot more okay with stuff like needles and simple procedures, and will even agree to necessary surgical interventions.
If you create a learning environment that allows more for self-directed learning, and involves less specific testing, most kids actually will enjoy learning.
The way kids hate school, and are afraid of doctors is the result of those interactions being associated with violence and coercion. The hatred is because of the coercion, rather than the hatred making the coercion necessary.