If Israel is able to build wherever it wants without anyone stopping it, then so be it. But I am not sure that Abbas is the only one laying down a red line beyond which he does not want Israel to go. If the international community does likewise, Israel might find itself having to make some very difficult choices based on what it thinks is in its best interests.
Labor court orders Jerusalem light rail operators to return to work (Haaretz)
from the article: Abbas: Israel's settlement plans in area E-1 are a 'red line'