Well, there's an article on Haaretz today that might answer one of those questions. And this article is by no means out of the ordinary.
The jist is this:
Some 90 right-wing activists on Thursday besieged an Israel Defense Forces post north of Ramallah, in protest against the civil administration's decision to remove construction supplies from an illegal outpost in the West Bank.Israeli settlers were about to start building a house, or houses, in an unapproved area, so the IDF showed up and carted their construction materials away. This may partly answer the question, Why can't they just stop letting in more settlers?
The settlers rallied around the civil administration officials, pierced the tires of a supervisor's car, and sicked a dog on one of the soldiers.
Illegal settlements have been dealt with in a multitude of ways. Sometimes the government ignores them. Sometimes the government gives passive support. Sometimes the government gives active support, like providing IDF guards to protect the settlers. Sometimes the government evicts them. No doubt the Israeli government's reaction to each settler has more to do with the strategic placement of that particular settlement, and whether it supports the land grab, but illegal settlers are not always supported wholeheartedly.
However, when the IDF does take any action against Israeli settlers, the backlash is fierce, both immediately and long term. In the short term, you have attacks like in the Haaretz article above. You have settlers spitting, yelling curses, and the like, at their IDF brethren. Calling them traitors. In the long term, well.
In 1947, David Ben-Gurion struck a deal with the orthodox Agudath party. In exchange for implementing Jewish law as national law in the new state of Israel, Agudath supported Ben-Gurion politically and he became the well-loved first Prime Minister of Israel.
Ever since then, the orthodox Jews in Israel have had extraordinary power over the government. One cannot win office without their support. And once in office, one would be swimming against the tide to try to accomplish anything without their support.
And they support Jewish settlement of the West Bank.
So any Israeli politician who dares to remove settlers from Palestinian areas will first have the soldiers they send spit on, cursed, and possibly beaten, and then they will be booed out of office.
This is the state of affairs.