On Advance Search - Search Ascents field Country: is for the ascend in which country it is made not for the origin of the climber which made the ascend.
Another criterion that should be added to ascents search is date interval . IMO this is very important, since, one would thus be able to find ascents into one's desired grade interval within a country that are suitable or ideal for the specific time of the year s/he intends to travel. And travelling is the essence of climbing, of course.
sugestion - Search Ascents - new search criteria