Some folks have a much more limited view of "basic" than others.  Walker might mean something like "getting your finger stitched up when you slice it open while opening a can of cat food" (not that I've ever done something so stupid... at least not more than once).
My idea of "preventative care" includes stuff like colonoscopies (I'm of that age) and my current insurance doesn't really cover them, so it's hard to imagine that they'd be covered as part of a "basic" program.