Security at the airport

The security procedures at Changi airport is excessive and is causing a lot of inconvenience. Here is my experience.

1. On arrival at the airport terminal, I have to screen my bags. Why is this necessary when the bags are also screened at the check-in counter and at the boarding room?  I suspect that this is to prevent a bomb going off before check-in. Is this so important?

2. Before entering the departure hall, I have to show my ticket and passport to the policeman.

3. After going through the automated gates and have my finger printed, there are still people to look at my passport. I recall that this procedure was implemented when someone passed the immigration desk though with a wrong passport. Do we need to over-react to this mistake by introducing another set of check?

4. Before entering the boarding room, I have to go through a detailed screening. The laptop and mobile phones and other metallic objects have to be removed  In spite of removing so many items, it is likely that the metal detector will beep and subject me to a physical check.

5. I still have to show my passport to the staff who scan my ticket.

Altogether, I have to show my passport three times and have my bags scanned twice. I suspect that more requirements will be introduced to combat other security concerns. The question is - are these measures overdone?