Stone stairs and slabs don't drop cobbled variants

Unless the player has silk touch, if a player mines ordinary stone with a pickaxe, it will always drop cobblestone.

However, if a player mines stone stairs and slabs, they will get stone stairs and slabs, rather than their cobbled varient, regardless of whether or not they have silk touch.

This doesn't really make sense as stone drops cobblestone but stone stairs and slabs don't drop cobblestone stairs and slabs.