Seems he was not forced to wrestle against girls only.
He was born female? Seems to me he should be allowed to wrestle as a boy if that's what he wanted. In fact he was: During high school, Beggs also had finishes in boys' division tournaments, including third place in Greco-Roman (3 person bracket) and third in freestyle wrestling at the USA Wrestling Texas State Championships in 2018 (6 person bracket).[9]
I guess I fail to see how he was harmed as he wrestled in both boy's and girl's competitions
This may be the case in California and other "liberal" places. But in Texas, a trans boy is not allowed to play a boy's role in a school musical theater.
This student does not have any unfair advantage, and does not pose any danger to other students. His existence itself is morally unacceptable to many people there. 55% of Americans (84% of Republicans) think changing one's gender is morally unacceptable.