This request by Netanyahu has raised the ire of many and sparked a national debate about what to do. As a millionaire on his own, if he feels he or his family is in danger, perhaps he should finance his own security, or maybe the State should provide it even past the allotted amount of time former Prime Ministers normally get protected. 

While the decision revolves around a lot of money as State protection would continue to grant the Netanyahus a  security details including a car and driver among other things, I think the decision should be purely professional. Netanyahu's security needs, if there are any, are not because he was in private business and perhaps ticked off the wrong people. Netanyahu served the State of Israel and it is due to serving in that capacity he feels he needs continued protection.

the considerations should be purely professional, not political. The Shabbak should look into the threats (as I am sure they already are) and decide if extending the protection of the Netanyahus is warranted and necessary due to credible threats or not. If the threats are credible, his security should be funded by the State, as the threats are coming in due to his service of the State. It should not matter whether he is right wing or left wing, liked or reviled, on trial for alleged crimes or being framed - he served the State for a long time and any threats to him and his family are due to that service and for that he should be granted extended protection (if the threats are credible).