In practice we've seen that the oppressed usually don't go on a massive revenge killing spree. Take for example the end of slavery in the US, or the end of apartheid in South Africa. Were all the white people murdered in revenge? No, even though many probably deserved it.
I'm sure most Palestinians would be open for having a single country with equal rights and no apartheid from the river to the sea shared with the Israelis. Israel will never accept this because they want to maintain their apartheid and white supremacy.
The Israelis have every reason to continue to be worried about palestinian terrorism. A one state solution would involve them losing control of the government. Maybe the palestinians that would make up the majority would be nice to the Israelis, but I really really doubt that based on the way theyve treated the israelis over the past century. They certainly would attempt to institute sharia law which is probably enough of a reason for Israelis to reject a one state solution.