I thought they explained why they locked overclocking with the 58003DX previously. In any case, Intel have been locking CPUs artificially from OC for decades. I think we should not muddy the water by bringing CPU as a comparison.
On the GPU side of things, I am not happy with AMD slowly limiting things that we can tinker with for sure. For example, limiting how much the slider can move to overclock either GPU or VRAM is annoying. This is basically to make sure that the product don't cannibalize sale of a more expensive model. In this case, it will likely only impact power users since most people may not tinker their hardware to such an extent.