everywhere i’ve looked states this as a fact but never actually explains why
Two errant fields interacting do not produce a force. A force has to act on some object, and for a simple explanation fields are not objects and do not feel force. Now multiple magnetic fields do interact with each other, but it is in an additive sense where the strength of the net field is what matters at any given point. When a magnetized object is placed in the field it then feels a force that is proportinal to the field strength and direction at that location. Forces on their own really mean nothing, they are just useful ways of describing interactions between objects (classically).
I’m afraid there’s not really much that can be done to simplify this down. It’s sort of just the way things are. It’s a bit like asking why two bodies with mass are attracted to each other. That’s just how gravity works.
You could think of it a bit like this: magnets produce magnetic fields. These fields then cause other magnets to want to move in particular directions. It’s like saying that gravity causes space to curve, and the curves cause mass to move.
I hope somebody can give a better explanation to this, but it’s a pretty fundamental question that you’re asking, and they tend to be harder to answer in physics.