The attempted genocide of the Founders wasn't a Federation tactic, it was Section 31 acting on their own. So even then they did not "endorse the use of genocidal tactics".
From what I have read and seen of Section 31 so far, I very much doubt that you are right. Unfortunately it was a long time ago since I watched DS9 and Google didn`t show me all the details. Nevertheless, I remember being left with the impression that although it was Section 31 who did it, there were high ranking Starfleet officers who backed the plan. Does Bacco really not know what happened? I find that hard to believe.