Blowing up buildings and jam-packed refugee camps, knowing fully well that it'll create mass civilian casualties is a war crime. And I'd rather take the word of experts rather than a nobody over this.

Quoting from the article itself

But human rights groups have previously said that Israel’s pattern of deadly attacks on residential homes display a disregard for the lives of Palestinian civilians and argued they may amount to war crimes.

The article quotes a previous article Human Rights Watch: Israeli war crimes apparent in Gaza war

Human Rights Watch on Tuesday accused the Israeli military of carrying out attacks that “apparently amount to war crimes” during an 11-day war in May against the Hamas militant group.

The international human rights organization issued its conclusions after investigating three Israeli airstrikes that it said killed 62 Palestinian civilians. It said “there were no evident military targets in the vicinity” of the attacks.

So yeah, brush it off as "Mistakes happen" somewhere else