"Debunking" isn't a matter of disbelief so much as it is a matter of removing the "bunk" that might exist in a specific claim. For instance, if a traveling salesman were to come to town and claim that his elixer could remove stains, cure insomnia, remove warts, and restore lost hair, a "debunker" would question the claims and demand evidence prior to allowing this con-artist to fleece the willing and believing public of their money.