It's not that Oromo's ''dislike fighting,'' it's that, Abiy's men have been more brutal than even the previous era, he even said ''you did not see tigray fighting their leader, meles, so I should be treated the same way in oromia.'' basically, he wants blindly loyal followers in oromia.
OLA is not doing bad though. It had to build an entirely new army from scratch, with no weapons, no funds, no support, except from its people.
it's not like tigray, which was stashing heavy and light weapons for years upon years, and had stashed billions of dollars, and had about 250,000 forces who are/were all loyal to their people