I'll play along....Lets break this down:
"They have 7000 kids at one high school, and that isn’t an exaggeration." - Ok, the 3 Plano's have 1k less and they all suck at football. How do you explain that? I live in Frisco, where we have 10 schools and all but one are god awful. And our numbers of athletic participation (especially football) decrease every year, yet out district is still growing...
"The only reason the school is like that is so they can field the best football team possible. Academic & social environment & giving the most kids possible a chance at participating in extracurricular activities be damned." - This is 100% false. You think the only sport, club, extracurricular activity at Allen is football? Their schools, and facilities, and programs beat out most colleges. Remember, this is coming from someone who lives in Frisco. We have nice schools, but they don't come close to Allens.
"Also, their football team recruits and adds transfers in like crazy. Kyler Murray was one of those kids to top it off. In short, the school is pretty much an embodiment of all the worst elements of high school/youth sports in our society." - Good football programs recruit themselves. If you think kids don't move for athletic purposes to other schools you are crazy. In Ft. Worth they move to Aledo, in Frisco they move to Lonestar. Shoot there are tons of districts in the state that have "open enrollment" and "school choice" where you can live outside the school boundaries and still go to whatever school you want (Katy ISD- looking at you Katy HS). Also whens the last time a 5* or 4* has transferred into Allen during HS? The last one was Kyler Murray. If you're from around this area you actually hear more about athletes leaving Allen than you do moving there.