A Tale of Two Irregularly Sized Mailpieces

I mailed Valentine cards to my mom and mother-in-law on Monday. MIL's came back to me today with the following sticker on the front:

Return to Sender
Additional 13-cents Required for Non-machinable Surcharge

This mailpiece weighs 1 oz. or less and cannot be processed on Postal Service letter-sorting machines due to one of the following:

a. It has a square shape
b. Its height exceeds 6-1/8 inches, or its length exceeds 11-1/2 inches, or its thickness exceeds 1/4 inch.
c. Its length (dimension parallel to the address) divided by height is less than 1.3 or more than 2.5
d. It has clasps, strings, buttons, or similar closure devices
e. It is too rigid or contains items that cause uneven thickness.
f. Its address is parallel to the shorter dimension.

* Affix 13-cents additional postage, remove this label, and remail.

My unforgivable (at least in the eyes of the USPS) sin was 'a' - a square envelope. Now, is it just me, or do some of these rules seem a bit ridiculous? 'c' sounds like a problem you'd get in math class. Were you aware of all of these rules? Because I certainly wasn't. Obviously. Or I would never have chosen a square card and envelope.

Now, I do understand that a service request which causes the business to go above and beyond the call of duty costs them extra money in manpower. For example, when I worked at a bank and a customer came in wanting a copy of a check that they wrote two and a half years ago, we charged them for it. After all, an employee had to be pulled away from their regular duties to go look through rolls of microfiche (do they even use that anymore?) which was not only time-consuming, but a pain the arse. Extra work = extra fees. I understand that.

But, in this case, my question is .... why couldn't the postal employee who took this envelope out of the reject bin to plaster the big sticker on the front telling me what I did wrong and then to place it back into the outgoing mail just use that couple of seconds to hand-sort it? Wouldn't that have been just as easy? And taken about as much time?

Just another fine example customer service.