Thanks for playing devil's advocate.
I don't know that I agree with A. Bunkers might sometimes turn out to be more penal than a hazard (and this rule is a big part of that), but I don't know that they're "supposed" to be. Who says? I think the overwhelming majority of the time, they're less penal, and they're generally regarded as such. Take for example the Road Hole bunker… people have managed to hole out from it. If instead of sand there were two feet of water there, everyone would take a one-stroke penalty.
And I don't know that I agree with B either. Water hazards have distinct lines, and thus you can estimate where they crossed the lines. There are no such lines in tall grass (through the green), and since you've lost track of your golf ball, stroke and distance makes sense.
Hazards (water or sand) are not through the green. You can play your ball - without grounding your clubs - from either hazard. Yet from a bunker, you can't drop outside the bunker as you can from a water hazard, despite there being a very clear line that separates "bunker" from "through the green."
I remember watching the Memorial a few years back - and it was discussed that Jack removed every other tyne from the rakes, so that the bunkers couldn't be raked perfectly smooth. As the bunkers should be a penalty... and the way bunkers are manicured on most courses, players almost always prefer a bunker opposed to being in the rough.