This is an extremely complex history. There has been a lot of change in the last 75 years. For example, saying Israel launched a major offensive is very misleading. They didn't even have a regular army and were outnumbered many, many to one. A cardinal reason the Arabs rejected the UN charter was they were very confident they would annihilate the Jews. Much of the land that has changed hands over the course of Israeli history is a direct result of IDF success in repelling Arab aggression.
The primary change in the last 75 years is the emergence of Israel as an economic, military and political power. IMO, their own leadership has not recognized this and steadfastly refused to work towards peace and acknowledging they will have Palestinians as neighbors. Israel is cruel to Palestinians and has no path to peace with their current policies. They need radically different policies because the Palestinians have nowhere to go and will soon outnumber Jews, if they don't already. Gaza is a prison or a refuge camp at best. People can't live like that indefinitely.