Hi guys! I'm new to the group, from chicago and just wanted to comment on this thread.
I really don't know the reason either, lol. Like it was said previously "thats just the way it is"...
When I started back in the early 80's we always used those beloved ivory crackle finish metal outlet plates ( before this plastic revolution), and anyone who worked downtown near our beloved 'el' trains can tell you about those 6-32's working themselves loose and the plate hanging there balanced on the hot blades of those not all the way plugged in plugs!!
i always believed for safetys sake the ground hole should have pointed to the left ???