John Kerry

given how unpopular criticizing Israel in any way is, why did Obama allow the abstention and why did Kerry speak out.

I think the reason is that this is the final point where Israel could turn back. If, as seems likely, Netanyahu's legacy will be to have created a Greater Israel - in land mass - that will abandoned most of the idealism that existed when Israel was first an idea and then a country. Liberal Zionism, which the lion's share of American non Orthodox Jews believe in will be dead and supporting an nation that is overtly apartheid will be impossible for a large percent of American Jews.

One observation -- It is in some ways fitting that John Kerry is ending his time as Secretary of State speaking an unpopular truth - just as he did when he first gained public attention as the very intelligent, eloquent, 27 year old speaking to the SFRC. He will have, among other things, been the essential person for getting the Iran Deal, which avoided a war, and the Paris Climate Change Accord and several other environmental accomplishments during his time in power. The fact, that after all these years, gaining the power he has had and owning the accomplishments he has, his public time (up to this point) has as bookends, two very tough courageous speeches speaking truth to power. He is one of the very few politicians who have spoken of moral duties and he has lived up to them.