It is not so that the Buddha rejected aversion at all. The path is not just an "increase of love" (e.g. greed), but to develop a lot of dislike and aversion in regard of what is akusala ("unskilful"), and like and desire for kusala ("skilful" -- from ku = bad, sala = cutting away -- so even the word for "good", skillful, wholesome, carries a very sharp cutting away of root).
There are times, inwardly or outwardly, where aversion is required; times, inwardly or outwardly, greed is required. For each situation it's different, and it's required to know of what is good and bad very clearly, and simply follow it.
One should not have to less aversion in regard of one's anger -- and it's suggested to kill it right, if appearing, and make its total liquidation one's foremost project: sometimes requiring aversion, sometimes greed, all however based on wisdom (but if basing on one's bias or preoccupations, for sure there will be circle-drifting, and mis-investigation of what has come into appearing).
And to have spoken here of right effort: it's good to investigate this factor more carefully. Sure, one may place improper aversion here to do so... and fools himself in both directions at the same time.
Just to get sure: there is no skillful, good, aversion which causes other being's destruction of life, depriving of their possessions, abuse, depriving of truth. As pointed out by the Buddha: neither affection (love) nor hostility can can end conflicts but are abandoned by non-hostility. Again requiring a lot of aversion to abound (abandon) and cut off non-beneficial.
(Note: Neither given for trade, exchange, other stacks, worldly gains and down-binding entertainments)