I was trying to unravel the enigma for months but I just left it alone as it's cutting into my other work!

From what I gather, they're hoping you confuse the addresses and send coins there thinking it is yours. They probably do jack the existing keys while they're at it, all of which is automated so no extra effort for them to cover all bases.

Or maybe some noob accidentally misconfigured their virii, who knows, lol.