The snowball clause is not policy, but it is designed to prevent editors from using RuneScape Wiki policies and guidelines as a filibuster. For example, if an article is deleted for a reason not explicitly listed in the criteria for speedy deletion but it would almost certainly be deleted via the Requests for deletion process anyway, there's little sense in undeleting it. In the case of "controversial" speedy deletions, creating a single RfD for the page may be the better course of action, as opposed to having two or more editors war over the page.