Nobody disagrees that Israel is building illegal settlements on Palestinian land beyond the borders originally approved by the UN.
I think it was wrong for the UN to approve the creation of Israel in the first place. Thus, despite Israelis unfairly receiving their own state in the Middle East at the expense of hundreds of thousands of innocent Palestinians who were left homeless, Israel still refuses to stay within UN-designated borders.
The UN fully acknowledges that Israel is unlawfully building settlements on land that does not belong to them. It should go without saying that the Palestinians are allowed to defend themselves from their land being stolen from them. Thus, the resistance of the Palestinians is justified.