Question: Why do we sometimes have inexplicable aversion of some sentient beings ‘naturally’?
Answer: Generally, when we feel averse towards anyone (human, animal or otherwise) for no apparent reason, this might be due to some forgotten unhappy experiences in a past life or more.
It might be due to those beings having given us some suffering, thus having fear. Or we might have given them some suffering, thus having uneasiness due to underlying guilt unaware of. In any case, we should transform the negativity to be positive and pure, by relating and responding with compassion and wisdom.