They wont turn them into sec moderns they can look at a range of other types of schooling.
If you give parents a choice between grammar and secondary moderns then 95% will want a grammar. That means that non-selective schools will only contain those who didn't pass or didn't take the exam because they wouldn't have passed. It doesn't matter whether you call them sec mods, upper schools, specialist schools, schools for the rest, they will be schools for those who failed. And that causes all sorts of problems as we see in Bucks, Kent, Lincolnshire and Trafford.