Yeah, I guess the question is, what are you hoping to achieve by hinting at these facts? Diminishing one atrocity by pointing to another is always going to sound kind of gross. Especially to the people who have a connection to that atrocity. As you say, it's very difficult not to hear it as relativising human life, or in this case, blame.

That might even be somewhat appropriate in a conversation where somebody is apportioning blame, but when an atrocity is simply mentioned, it speaks to a certain defensiveness, or a complete lack of empathy, to feel the need to pull out a historical scorecard.