This answer to Why is the magnetic axis of Uranus and Neptune off center? in Astronomy SE perplexes me, partly because I can't understand the block quotes and partly because they constrast those planets with Earth and Earth's dipole is off center as well and it's field also flips back and forth.
Question: Is it possible to write a simplified, plain-language summary of what this explanation for why Uranus and Neptune are different than Earth in having large offsets of their dipole field?
From the linked answer, which is sourced from Nellis 2017 Magnetic fields of Uranus and Neptune: Metallic fluid hydrogen:
Earth's axisymmetric magnetic field
The most researched magnetic field in our Solar System is, of course, Earth. Nellis 2017 explains how coupling between the rotational motion and convective dynamo motions in the Earth's outer core cause the magnetic axis to drive towards alignment to the spin axis:
Because rotational motion (RM) of Earth is strongly coupled into convective dynamo (CD) motions of its fluid-Fe outer core, planetary RM stabilizes convective motions that generate a dipolar magnetic field. If a convective fluctuation occurs which tends to destabilize a given dipolar axis, then strong RM-CD coupling either drives convective motions that essentially restore the initial orientation or CD fluctuations that drive the initial magnetic axes out of orientational equilibrium are so strong that RM-CD coupling eventually drives the dipolar axis into an alignment anti-parallel to its initial one.
Uranus/Neptune non-axisymmetric magnetic fields
The magnetic generation near the surface, as well as the H-HE envelope (again according to Nellis) means that:
local convective dynamo motions of fluids that produce the magnetic fields are essentially decoupled from global rotational motions [...]. The dynamos of U/N would then be relatively free to wander as local convective fluctuations dictate. Thus, tilt angles and center-offsets of their fields would vary slowly over the age of the Solar System.