Yeah, that's a letter my friend had to write to his math teacher in like 11th grade apologizing for calling one of his classmates gay.
edit: This is it.
Why calling people “Gay” in public places isn’t appropriate
It’s inappropriate to call people ‘Gay’ in public places. There are multiple reasons for this. For one, there is nothing wrong with being gay. Calling someone gay as an insult makes it seem like there is something wrong with being gay. People may be gay, or have gay friends, and hear the comment, and be offended. Secondly, the person you call gay also may be gay, and it is important to accept different lifestyles to give everybody an equal and fair chance at life. Another issue is during class, insulting someone interrupts the lesson and disrupts peoples learning. Calling my classmate gay was inappropriate, and I’m sorry.