They provide all the tools TFA suggests/recommends and more[0], strongly shifting incentives towards a view only manipulating its own DOM (which becomes as cheap as or — in some case — cheaper than manipulating the global DOM).

[0] for instance both Backbone and Spine provide a declarative mapping of events triggered within a view's DOM to a method of that view, making handling of events arising from one's DOM much easier than handling events from outside; Spine also provides a mapping for sub-elements of a view's DOM automatically setting them on attributes of the view making DOM manipulation itself simpler.