Air Dragging. Due to the fact that it's always daylight at the equator of true north (on a concave Earth that we live inside) then it only makes sense that air will always be the most stable at true north thus all other air is slightly less stable so when you spin a top with only 1 possible axis of movement it will naturally stop on the path of most resistance. And due to the fact that the sky is moving on an axis inside the Earth then it would be natural to have the point of axis which is the North Star naturally cast have a line of resonant drag. (Another fact is that it is easier to spin a top clockwise then it is counter-clockwise, this is also due to air dragging and because momentum always follows momentum if the Earth were spinning counter-clockwise it would be easier to spin counter-clockwise in tops but that simply is not true)
(If this theory is correct it would also explain why there is more hurricanes, cyclones and tornadoes near the equator)