I have been into the USA and Canada, and the UK and been subjected to a number of questions at Immigration, to assess the purpose of my visit.
I have also been questioned in NZ and Singapore but less so.
Every border has the right to ask a questions or five to assess if you are suitable for the visa you have - even if its a visa on arrival type of entry.
Equally holding a passport and an airline ticket does not give you an automatic right to enter a country.
If you are entering Israel the legitmate reasons, answer the questions truthfully and you will have nothing to worry about
I do not understand the reasoning for your questions