"I couldn't be mean in school..."
Or are they saying "I couldn't be me in school"?
Oh, maybe! The subtitles were clearly auto-generated, not real ones.
That's just bullying, and it seems pretty damn external to the child. Not an inner essence, not a deeply held self identification. It's the same old listening to other people tell you who you are
But that's the story behind so many trans people. Bullying and abuse when developing self-identify leads to gender dysphoria. Those people need therapy not double mastectomies 
Yes, I agree. Bullying and abuse (which are external) aren't revealing something intrinsic and eternal; more often than not, bullying and abuse lead to harmful distortions in young and/or fragile egoes. This dynamic applies to many, many children, and if we try to help them withstand negative thoughts (and prevent them from internalising those negative thoughts), how would we know that it is "obviously different" in a few cases? We don't. Therefore, yes, it makes far better sense, and is far more humane, to work on repelling the negative voices (or even "creating your inner cheerleader") before attempting to question identity.