and he gets modded down multiple times by the same user via proxy accounts. I've gotten it too, where it was obvious (specifically on two, maaaybe three occasions) that the same user modded me down three times.
"Nothing's obvious unless you are overlooking something." I've personally verified that it wasn't happening to the person you called out. Narrow down the time frame for me and I'll probably verify that it hasn't happened to you, either.
Yes, people have often jumped to this conclusion. So far, they have been wrong every time. But it is human nature to form such conclusions. Some examples: 590525, 652529, 974370.