I don't think you've quite grasped the point I was making earlier.
How many things/groups/dhammas etc. can you avert your mind (placing attention - manasikara) to at once? For me the answer is just one.
Of all the things I could avert my mind to, out of the vast number of dhammas I could fabricate, I see no compelling reason to avert it specifically towards child abusers. More likely than not, the mind would be better placed on the six-sense-sphere, the five aggregates, the qualities of the Buddha, the qualities of the Dhamma, the qualities of the Sangha, the breath etc.
Out of interest, do you ever feel compassion for the endangered Guatemalan Tree Walrus? Not likely, because I bet you'd never before brought it to mind until I mentioned it. Yet, that doesn't mean you regard it with hatred or other unwholesome attitudes either.