Sometimes we like to focus on some smaller detail to such a great degree that we miss the rest of the view, taking a small piece of information out of context and applying it broadly to an aspect it doesn't exactly fit. Poor Applebloom seems to have fallen victim to this unfortunate fact of life.
Spongebob's house: Something apple
Failed attempt at humor, or do you not realize it's a real fruit?
Pear: MOULDY APPLE THROW IT AWAY MISS CHEERILIEEEEEEE!!!!
You know, at the core of it all, this is all your fault, Cheerlilee.
YOU ARE FAILING THESE CHILDREN. AND NOT IN THE SENSE OF SIMPLY GIVING THEM POOR GRADES.
Although hopefully you're doing that too.