Aside from the fact that the settlements are illegal, they ARE an obstacle to negotiations and peace. Israel is in violation not only of its previous agreements, but also international law. Freezing their continued expansion is NOT a concession, it's a lawful DEMAND! And in case you missed it, it's not just the Palestinians who are making it.
Bomb in Lebanon targets bus heading to Syria, no casualties (Reuters)
from the article: Peres: Google and Facebook will bring Mideast peace