I must be explaining myself poorly because what you just said makes no sense to me.
I interpreted it as a support of the non-container system, with corpses re-equipping their clothes that passively happen to end up on their tile. This system would then be broken by a dumping change that decreases the chance of that occurring. If dwarves are actively putting them in the same destination then there isn't an issue. However, it would beg the question why they wouldn't just haul everything as a single object to begin with.
The remaining part I didn't quote appears to suddenly switch back to supporting the container system, for a given reason (besides the stated less dwarves and clothed burial) that's difficult to follow under the assumption that the first part is about the opposing system.
It makes a bit more sense if
this post is talking about items being removed from container corpses. Of course, we all know how silly the idea is that dwarves would ever willingly remove items from a container, given a choice.
Anyway, to clarify my first post in the thread:
Corpse containers are great because they keep everything organized. Sometimes you get multiple corpses on a single tile.
Everything automatically ends up neatly in the corpse stockpile. In the event that the stuck-in-bin issue is fixed, the corpse contents being forbidden on death will still prevent dwarves from hauling the deceased's belongings to separate stockpiles.
When a limb is severed, the associated clothing will travel with the limb instead of being dropped at the feet.
Another benefit of the container system: Burying a dwarf in ceremonial clothing and not having a naked zombie.