The spam from killing mobs is unfortunate, however I don't think it can be removed unless we remove the messages completely.
Actually, there is a thing you can do there - since MobHunter V3.3.4 there is an option of integration with ActionApi
, so messages aren't being sent to chat anymore, but they are shown in the actionbar - like this:
Note: with latest version and default config I didn't managed to get MH send those annoying messages on my localhost, so maybe you are using some obsolete version or some wired config change here or there...
EDIT: Sorry for misinformation, it actually shows almost everything but those annoying messages in the action bar...