I don't know. Why does anyone care that much about high school soccer for their kids?
Because its fun. My son absolutely loved it. Trying to make the varsity team as a freshman, playing with his schoolmates and meeting new kids from the school that he now had something in common with, going to practice after school with that kid from Spanish class, that kid from biology, the silent nods from the upperclassman when walking down the hall between classes, the comradery and sense of pride when all the soccer players (Freshman, JV and Varsity) wore their school soccer polo shirts on game day, riding on the bus to an away game, having the cheerleaders make a poster with the boy's name on it, having the girls team cheer them on during their playoff run, playing in a stadium filled with parents and classmates, etc., etc.
HS soccer may have its negatives, but in SoCal, at least at our school, the coaches for the Varsity and JV team are each local Club coaches and the same is true for virtually every school in our league. The kids that make the teams are almost all club kids and I can honestly say that my son's team played a better brand of soccer than his last two club teams.
We ask so much of our kids, do well in school, devote 2-4 hours a day to practice a few times a week (mine is a GK), chores, and other things that might not be fun. Humans (including our sons and daughters and especially our daughters) are social animals and playing for the High School team is just plain fun and an experience that club soccer does not provide.
When roughly 8-9% of kids will ever play in college at any level and the odds of getting a scholarship are even less, why on earth would we as parents/adults permit some A-Hole with US Soccer in Chicago to dictate to our kids they can't have fun for a few months?
Various scientific studies have found the
injury rate is slightly lower in HS soccer (2.6 per 1k AEH) v. Club (3.0 per 1k AEH). (see,
http://www.apta.org/PTinMotion/News/2017/3/22/HSSoccerInjuries/ and
http://natajournals.org/doi/pdf/10.4085/1062-6050-45.3.238?code=nata-site) Note, anybody claiming different is relying on anecdotal evidence, which is inherently unreliable.
Bottom line ... they are kids. If they want to play HS soccer let them. Its fun. If they don't, OK that is their choice. The only exception in my mind is if you have a truly gifted athlete that is invited to the US Soccer National Youth Team Camp. Otherwise, a few month break playing HS soccer isn't going to impact much at all.