Board Thread:ROBLOX help and discussion/@comment-7913013-20150708195226/@comment-26474029-20150711202049

Robloxy wrote: Why would they do such a damn THING! It's because many people are visiting Free KO/WO places and ROBLOX are getting bored about it, suddenly the KO/WO earners are gone.

But you can still  keep the badges  for KOs that you have though you can't get any new ones.

So regardless, that's why KO/WOs are removed.