The data density in bluray means that the pits are far, far, far, far too small for dirt to get stuck in, or on. Think of it like placing a pebble on a beach. There are pits between sand grains but the size disparity means it acts like a flat surface for most intents and purposes.
Not only this, but presumably the pits can be under the glass, just as they are under polycarbonate on a disc. Then the pits are not exposed to dir, and a normal washing will remove surface dust, bird poop, etc.
Do not feed their useless parisitism on our culture and public domain.
If you must be entertained, find alternative sources, from indie stuff all the way to pirating.
We must do this until their backs are broken.
They will fight.
There will be casualties.
We must not stop or compromise.
If you want to put yourself on the map, publish your own map.