It looks too selective to be a result of "random" damage (like getting stuck in a lawn mower), yet is not regular enough to be the result of incidental damage (like getting stuck in a damaged vending machine). I can only conclude it was hand-made, by someone with a sharp tool and way too much spare time on their hands. As for "why", well, you'll have to find them and ask them. Humans are not renowned for their logical, rational behaviour.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis