I really am grateful for JGWeissman for helping me click on the fact that light isn't something that obeys the wave described by the Maxwell equation, but is that wave. The difference is imagining light as a type of substance compelled to oscillate with the wave pattern, and there being a wave pattern, resulting naturally from causal interactions, that is interpreted by our vision as "light".

Thus this is the explanation I would give my past self for strikethrough(why light oscillates) what light is:

A charge creates an electromagnetic field. If the charge moves, the electromagnetic field will have to change. However, while the field is defined over infinite space, the field cannot update instantaneously over all of space. Instead, the field updates at the speed of light from the new position of the charge. At a small, fixed moment in time after the point charge has moved, the field has updated within a sphere of a certain radius, but has not yet updated outside this radius. What we call 'light' is the defect radiating outward though space like a ripple. When our eyes intercept this defect, we gain information about the point charge's displacement and -- in some way I don't understand, and don't need to for the immediate explanation -- the field no longer needs to keep updating and the ripple stops propagating (the waves collapses to an intercepted particle / photon).

So I no longer see light as a thing traveling though space, but as information about an updated field traveling in finite time.

Does this make sense? I suppose it could be completely wrong, but it is what I mean by a 'mechanical' explanation.

Oh, and I'll add that light oscillates because the electric and magnetic fields update each other in finite time, and there is a slight lag, so that the wave has an amplitude. I see this as analogous to predator-prey oscillations in a Lotka-Volterra model; if the fields responded instantaneously there would be no oscillation.