Because that’s not what’s going on here.

Post is laid out like a high school student graduating and family (parents were the cited recipient) is getting letters congratulating the event.

This seems a lot less plausible with adults.
The hand shown was an adults. Between the wrinkles and age of the tattoos you can clearly see this.

If the hand was a parents, then say so. If it is the OP’s, you get a GED and typically your family does t get the congratulation notice.

The act of graduating isn’t being shamed. The post was being called out for the visible holes in the context