I’ve just been reading about a similar upsurge of reports about anti-LGBTQ slurs and chants at high school sporting events. In one recent case, players and some student fans on the sidelines were taunting an out gay player by calling out “faggot" when he had the ball.

LGBTQ student leaders say incidents like this are on the upswing rather than decreasing. I suspect this is partly for some of the same reasons you named with respect to racism — that the rise of Trump and ultra-conservative leaders has emboldened people, even high school students, to speak up in negative ways that would have felt socially unacceptable just a few years ago.