This is reflecting the bias of the source material reflecting a society wide bias. I bet if a human evaluated all the text that the model was trained on, they would probably find that the material itself likely had an anti-Palestinian bias.
The Gemini example, however, did not represent the bias in the source material, but rather the biases of the Google management and engineers.
Reflecting the bias of the source material is unfortunate but understandable. Injecting your own bias on purpose is a different matter, and is assuming a level of control that invites scrutiny.