Look,they started this,but the ones who made it worse every time,were the Palestinians. Of course,the Israelis didn't help either when they let all these extreme right-wing settlers demand take more land from Palestinians inside the West Bank and Gaza,demolishing houses,destroying olive trees and occupying them.
However,Palestinian violence in terrorist attacks was what kept provoking Israelis to take stricter measures. First in the 60s,then in the 70s,in the form of hijackings,attacks on tourisms,bombings and attacks by PLO. In the 80s they had conventional warfare in Lebanon. In the late '80s they had the First Intifada. Israelis kept getting stricter. In the late '90s and early 2000s when the Second Intifada started,the amount of terrorist attacks by Palestinian groups,made the Israelis put more checkpoints,build walls and fences and basically turn Gaza into a huge ghetto.
Don't think that Palestinians don't have their own share of responsibility in this. If you see a list of their early terror attacks,but in the 60's and 70s when there wasn't the level of this oppression by the Jews,you will wonder "Why couldn't they try to solve this diplomatically back then? Why didn't they try to solve this peacefully? Why didn't they negotiate to get back to to the UN partition plan?"
Well I guess the reason is,because they wanted the entire Holy Land back,thinking they could defeat the Jews,just like that blunder in 1948.