Sure, it's just such an odd bundle of claims that were not fully interrogated in the essay. 1. That these things have changed from "small minority" to "significant minority" in public school populations, 2. they haven't changed similarly in private school populations 3. these things increasing are bad and undesirable for you and your child, and 4. there are not cheaper ways to fix this than sending your child to public school (the obvious point to me is if you don't like that there's a significant ESL population, or your community, move somewhere else!).

Language is an absolutely critical part of community, identity, socialization, and connection. Even just not sharing the same first language as another person begins to chip away at these metrics. Much moreso if you share no language in which you are both thoroughly fluent. It's not either person's fault, and it's true even if both parties have absolutely no racism or xenophobia or whatever in their hearts (though isms multiply the effect - even the unconscious isms that most people supposedly harbor).