Slow-candidates for hybrid attacks

could someone please enlighten me. Why isn't --slow-candidates enabled for hybrid attacks? What are the implementation issues? Naively, I'd think that most challenges should be dealt with/implemented for other attacks already and hybrids would be only about putting the pieces together? 

I think there isn't really any serious reasoning why it isn't implemented yet. You could try to request it on github ( and see if it gets accepted and implemented (or at least you get some feedback if there are some obstacles etc).
Well there was so I interpreted it as "rejected" feature. But I might give it a shot.