I disagree in that Abiy does know such strategy backfires. The last war is proof that attacking civilians turns people towards the leaders and away from Abiy and even ENDF.
I don’t know but my guess is Abiy attack against people is to help pro independence Tigrian faction gain popularity so they are able to take Tigray out of the union. This may give Abiy a better chance at maintaining power - in his mind - by taking a major stumbling block to his rule out of the equation. This is just a guess.