You can refuse

Under Israeli law, the police needs a court order to access your email, so, if Israeli police asks you if you can login into your email for them to read it, you can say no and there will be no legal consequences.

But, under Israeli law, entering into the country is not a right that all foreigners have, so, if you refuse to allow immigration officers to look into your email they can also refuse entry according to their own judgement.

It sounds heavy handed from part of the Israelis, if only your country was surrounded by enemies and and terrorists financed by foreign governments you would probably understand.

Despite the downsides, Israel remains the best country in the Middle East when it comes to human rights.