A pre-condition attempts to determine (part of) the outcome of negotiations before they are held. If Israel DOES freeze construction of new settlements, this does not determine the outcome of borders etc., so I wouldn't call the Palestinian demand a pre-condition. If Israel does NOT freeze construction, this DOES change the outcome of the talks. Such a freeze is therefore not a "pre-condition" to the talks, but a necessary condition for the talks to be held. Netanyahu no doubt is clever enough to understand this, but the rest of the Israeli public may not be. Even some members of the Israeli government seem to get confused by this word game. Of course, the commentators here are not among those expected to see the difference, so we can prepare for of flood of foolish self-righteousness.
Islamic State militants blow up ancient Arch of Triumph in Palmyra (Reuters)
from the article: Quartet to meet in Brussels in bid to restart Israeli-Palestinian talks