By default, schools you add are listed on your User Info page, along with the city, state, and years attended (if specified). If you want to hide your school or only let friends see it, then uncheck the Show your school's information on your userinfo? option or select Friends only in the "Who can view this information?" drop-down box on your Edit Personal Information page. However, these security options for your User Info page do not hide your journal's listing on your school's search page.
You can remove schools from your User Info page by following the instructions on the Manage Schools page.
That last sentence is not true; the previous paragraph says how to do that. What you can do from the Manage Schools page is remove your listing of the school entirely, since you may have already removed it from your userinfo (558350, you need supportread:schools for this).
Essentially, I propose that instead of saying adding or removing schools from "userinfo pages", the FAQ should say "listing" or "unlisting" (or even "adding" or "removing") schools, except where userinfo is exactly what it means. Thoughts? Pocky? Praise of my vast brilliance?