I think once you get a group of people all guessing it normalizes it within a family as well maybe?
It really is a perception thing I think, but yeah it can feel incredibly exhausting for us, instinctively oppo and I guess frustrating for them.
I had some insight once when a sibling was complaining about how they kept making excuses not to pick up a gift they'd accepted and they seemed genuinely angry the person was still offering and hadn't "taken the hint" they don't actually want it. It's flabbergasting to me but seems like that's really how they see things.