Having multiple parallel tracks for different types of students is controversial. Schooling tends to be cyclical with periods with more tracking is popular shifting to periods of less tracking and more classroom mixing. It really depends on what you want to optimize for. More tracking benefits the highest achievers. Less tracking raises the bottom and the average but at the cost of not maximizing the outcome of the top.

"Having multiple parallel tracks for different types of students is controversial."

It shouldn't be. The research overwhelming says its a good practice. The type of people who say this type of thing are the exact type of ideologically motivated people who are destroying school systems in blue districts. Ironically this group both hates private schools and creates the environment that pushes parents to pay for private schools. I've personally seen the bad consequences of schools that do this and I know people who aren't here anymore because of it. So please, for the love of god, stop talking about topics you know nothing about.