Some points:
"For the past 49 years – and counting – the injustice known as the occupation of Palestine, and Israeli control of Palestinian lives in Gaza, the West Bank, and East Jerusalem, has become part of the international order. "
In 1968, no one called it the occupation of "Palestine." When in fact did that occupation start? And indeed, on what date was the land no longer considered occupied Jordan? And why wasn't it called "occupied Palestine" when Jordan occupied it?
I've never seen a good timeline for this "occupation," perhaps because in reality it started out as a border dispute in 1949 and it remained so between two sovereign states until Jordan decided to withdraw its claim in 1988.
In a normal world, that would have given Israel full rights to the land.
Even though people hate to admit it, belligerent occupation is by definition the occupation of the land of a state, and practically no nation recognized Jordanian claims on the land and even fewer declared it "Palestinian."
El-Ad almost addresses this:
"Almost all aspects of this reality are considered legal by Israel. Israel’s control of Palestinian lives is unique in the careful attention the occupying power gives to the letter of the law, while strangling its very spirit. The occupation has so perfected the art of watering down International Humanitarian Law and Human Rights Law as to render them virtually meaningless. Once military lawyers, State Attorneys and Supreme Court justices are done masterfully chiseling out legal opinions, all that remains is raw injustice."
Once you remove the rhetoric, this is B'Tselem admitting that it does not have a legal leg to stand on.
The fact is that this is not about human rights of Palestinian Arabs, as B'Tselem and most of the world wants to pretend. This is about competing human rights between Israeli Jews and Palestinian Arabs. The great ignored fact is that the rights of Jews to live in Judea and Samaria, their ancestral homeland, is a human right at least as much as the rights of Palestinians.
And Israel does indeed try to walk the line between the competing sets of rights, not like B'Tselem which forced out an Arab human rights advocate, Bassem Eid, for caring about the rights of Jews.