>It is my understanding that the light is slowed through the medium because photons are absorbed and then re-emitted repeatedly.

That doesn't line up with what we observe. If an object absorbs a photon, it doesn't "remember" the direction the photon came from and then emit a new photon continuing along the same path - it emits a photon in a completely random direction. Yet we see light travel in a straight line, only bending when moving between mediums.

I don't think you can get a satisfactory explanation for why light slows down by thinking about photons. Light is an electromagnetic wave that exerts a force on the electrons in a material, the electrons oscillate and produce their own electromagnetic waves; do the maths and you find that the sum of all of these waves is a single slower moving one.