Word of advice, here as elsewhere: If you want to understand this, start with the primary sources, rather than with the talking heads and tendentious Op-Eds. (When I looked to the Washington Post this morning, for example (in print and online), I found a lead editorial condemning the U.S. abstention, a Netanyahu press release in the form of an article, and an Op-Ed by Elliott Abrams–but, unless I missed it, the Post did not offer its readers even a link to the actual views of the United States, let alone publish Ambassador Power’s fairly concise statement, to which the Post sources are, more or less, nonresponsive.)
Here is Security Council Resolution 2334, adopted yesterday by a vote of 14-0, with the United States abstaining.
And here is the statement by U.S. Representative Power, explaining why the U.S. neither supported nor vetoed the Resolution–including a description of the longstanding, bipartisan U.S. position on Israeli settlements, and an identification of the recently Israeli actions that prompted the U.S. not to veto this Resolution.
For an excellent summary of the Resolution, and why it is not likely to materially alter the legal status quo, check out this post by Elena Chachko on Lawfare.