They withdrew the Gaza settlers into the West Bank and used the Oslo Accords to justify the ever expanding settlement of the West Bank
Two different leadership coalitions. The coalition responsible for pulling settlers out of Gaza lost power because of the massive failure that was. And the alternative coalition (still in power today btw) who advocated for increased settlements in Gaza and in the West Bank won power.
Look at the numbers between 2000-2005 on this chart. The growth (192k, 226k, 249k) over that 5-year span is congruent with the growth you'd expect from a slightly younger-than-average population and a small ingress of settlers. Over half of that growth occurred in the three biggest West Bank settlements established before the Gaza pullout. So certainly some settlers in Gaza likely relocated to established settlements in the West Bank but not a significant chunk. Additionally, look at the settlements they pull out of in Northern Samaria (in the West Bank). They did that to prove that pullout was a viable option. Yes those settlements were small, but there's like 50 settlements smaller than the largest that they pulled out of.
And if you look at the biggest 10 settlements on that list, it makes up over half of the total population of Israeli settlers. And they're all like 15 miles or less from the '67 border. It's legitimately plausible for Israel to pull 50% of it's settlers out of the West Bank and fully pull out of 85% of the land area of the West Bank in just a couple of months. And more importantly, there is an active political coalition attempting to do that in Israel. But every rocket, every suicide bomber, every organized rape, every hostage prevents them from being able to be a big force again politically in Israel; because they're still seen as being responsible for the boondoggle that is Gaza.
You're mistake (and the HRW's mistake) is believing that the group of Israeli's responsible for pulling out of Gaza is the same group responsible for expanding into the West Bank. They're opposing groups. And as long as Gaza is non-peaceful; the group advocating for expanding into the West Bank is going to continue to win.
I'm doing the opposite. The path to zero settlements and zero settlement violence is peace in Gaza. As long as Hamas keeps breaking cease fires, the political factions who are advocating for the end of West Bank Settlements will never gain power and will never be able to implement a pullout.
As long as we in the West continue to invest massive dollars into Gaza and just accept that they use it to find their war machine, were perpetuating the settlement situation in the West Bank.
We can deny patterns in human behavior as long as we want to. But Israel's body politic will never accept a two state solution while their two state solution experiment has a hundred hostages and openly says they want to bomb, attack and rape them again. Stop being a child.