Object nonmention in «يَعْلَمُونَ» does not imply that learned people know every knowable thing, nor that others know literally nothing whatsoever. Such readings would misconstrue the comparison.
The focus is the characteristic of having knowledge, not an inventory of objects of knowledge.
This is why it matters to distinguish an objectless use of a transitive verb from a sentence containing an omitted but recoverable object. The search for one particular implied object can distort the stated comparison.