What a mess! And you will see another oops soon!!! :)
Don't worry too much. Accidents happen. And, luckily, not often!
I noticed that also many postcards from the USA have a small tear, starting on the right edge of the card, usually of 5 mm hieght and in the middle of the right edge, as if a postal machine hand grabbed the card at that side. However, I noticed that this happened less in the past time than in my early postcrossing years, so I thought USPS had improved the postal process... But this poor stamp...
I have noticed those little scratches, and thought they were nibbles form Mail Monsters... I think you're right that it's happening less. This sort of mishaps don't annoy me, really. What I really hate is where they attack the mail with a sharpie or a marker, because I think that is not an accident: it's lack of care.
I think that some vintage stamps are not quite tough enough for modern sorting processes. It gives me a new appreciation of the design of the stamp material, as modern stamps rarely seem to be torn this way. Sometimes the edges get torn where for some reason they don't always stay stuck down.
I think you're right.
Thank you for coming. All your comments make me extremely happy.