Reading his full opinion, it reduces to this:
* Israel declared itself exempt from the proceedings.
Therefore:
1. Israel was not obligated to provide the court with any facts, argument or documentation.
Hence, the court did not have the full facts at hand when deciding the case (i.e. Israel's reports on suicide attacks, data on prevention etc).
Therefore, the court should have recused itself from attempting to form an opinion.
Unless, the court was deciding a "contentious" case, rather than being asked for an advisory opinion!
One problem: that's impossible, since the Palestinians don't have a state, and any state that tried to bring one on their behalf would be vilfied and subject to US threats and maybe retaliation. Surely known to Mr Buergenthal.
He also states that had he been a judge in a non-advisory case on the wall, he'd probably rule against Israel, at least to judge by this:
"I share the Court’s conclusion that international humanitarian law, including the Fourth Geneva Convention, and international human rights law are applicable to the Occupied Palestinian Territory and must there be faithfully complied with by Israel. I accept that the wall is causing deplorable suffering to many Palestinians living in that territory. In this connection, I agree that the means used to defend against terrorism must conform to all applicable rules of international law and that a State which is the victim of terrorism may not defend itself against this scourge by resorting to measures international law prohibits."
Essentially the total content of the opinion he just rejected - or more accurately, the opinion he
accepts, but rejects, because it was stated in public.