The headline is more of a problem than the content.
The physical and mental benefits of taking part in sports are well documented. This isn't about little Johnny being forced to play rugby for half an hour a week for about 6 weeks a year in the very controlled, risk assessed environment that is a Tuesday morning PE lesson, I think we're talking about kids that are really into rugby, that play at a decent level outside of school 2 or 3 times a week, or the kid who tried boxing as an 8 year old and loves it and goes to the local boxing gym twice a week.
Increased exposure to the sport does increase the risk of brain injury and it is for (in conjunction with the child) the governing bodies of the sports, the local clubs and coaches and the parents responsibility to manage the risk. I dare say that there is room to improve in this area with all sports, but to suggest that allowing your son or daughter to play a sport that they love is child abuse is ridiculous and takes gravitas away from actual criminal child abuse.