So, there are two "results" in the event, useItem and useBlock. You are supposed to be able to individually deny or allow for each action. However, if useBlock is allowed, forge would also assume useItem to be allowed, no matter what useItem is.
Didn't check the newer versions of forge due to missing changelogs, but since it's a minor issue I assume it's not been looked at and therefore still exist at this point.
Thanks