I don't know people are pretty dumb. If teachers are sad about this they need to stop passing the kids on to a higher grade so that we don't have 16 year olds that can't read.
Call the parents in and make them responsible for their idiot off spring.
If a 16 year old can't read how does the parent not know?
I remember a man saying to me that his grandson graduated and couldn't read, he was so upset. Well duh didn't mom and dad notice? Guess not.
Parents need to be made accountable for their kids and teachers need to start calling parents and letting them know that junior is not too bright.