You'd be aware the the Palestinian state doesn't claim the Golan Heights?
I think that Israel has lost a lot of moral authority in the years since the 1980s.
But I think in 1981 annexing the Golan was a defensible choice: the Syrians had constantly used them as place to launch artillery barrages against Israeli towns like Tiberius.
The 1980s (especially the early 80s) really were different: there were Arab states around Israel who would use their own armed forces to attack, and the PLO hadn't disavowed terrorism.
Now of course times have changes, and Israel no longer can claim that those threats, and settlements have made their problems worse. But Hamas and Hezbollah have capitalized on that, so.. there is plenty of blame to go around.