Those marks look like they're the work of CNC or some other automated, robotic means. They look similar to the holes made in flywheels/harmonic balancers, etc to balance them, if that makes sense. I know there's obviously no reason to 'balance' an oil pan but hopefully someone knows what I'm talking about.
The marks look way too dead on to be made by a human being with a handheld drill. I can't imagine this being sabotage or anything of the sort. If it was, what was the point? The car doesn't appear to be losing any oil from that spot. Is the idea that the aluminum will eventually corrode in that area and make a pinhole, thus a slow leak?