My crystal ball tells me you're confused by the fact the the generated symbols are not interned: while the symbol's name is G564 it is not the same symbol you get if you (read-from-string "G564") because it is not added to obarray.
Maybe the simplest fix is to (put ',key 'lispdoc-section-handler ,sym) so you can just check (get key 'lispdoc-section-handler) rather than having to loop over the obarray.