I mean if you really want most of the finger-pointing should be at the Night Elves. The bulk of the conflict on Azeroth, especially in the Warcraft games, stems from Legion interference, invasion, or fallout from Legion actions. The Night Elves are the ones who originally brought the Legion to Azeroth.
More to your question I was looking specifically at events that fell under the direction of the Horde leadership. The decimation of Quel'Thalas was not under the Horde. Grom going rouge and drinking demon blood again was not directed by the Horde. And so on.
Who were partially drawn to the Orcs because they still carried the mark of the Legion from their previous enslavement.
I mean I get what you're trying to say but relative the broader events listed the skirmishes on the outskirts of Ashenvale were relatively minor and the massacre where Cenarius was killed was under the Legion's sway.
A few battles in the forest is not, in my opinion, equal to the burning of Teldrassil or the blighting of Gilneas, for example.