Many Lemmites don't have the knowledge from previous social interactions to think in any other way.

Child does not want to eat more -> parent asks child to eat one more bite -> child says they can eat two bites -> parent asks child to eat two bites -> child learns to only tell parent they can eat two bites if they want to deal with a parent asking them to eat two bites -> child learns to only tell parent they can do X if they want to deal with being asked to do X -> child learns to only tell parent what they can do if they can deal with being asked to do it -> child learns to only tell parent things if the parent will handle it in a way that helps them.

To be fair, this is a good life lesson to learn with employers, cops, judges, inspectors, teachers and other unilateral authorities, but it would be nice if a child can trust their parents with anything.