Sorry for stating the obvious, gents, but security isn't there for the convenience of passengers. If that was the primary objective, there wouldn't be any security at all, you'd just breeze straight through from taxi to plane and be on your way. The different standards from airport to airport, day to day, line to line is surely because there is no common standard. But that has the effect of making it very hard to plan an attack, which is the real point of security. No one thinks that any individual security officer will stop an individual attack, but the chaotic and unpredictable totality of the process makes if very hard to plan an attack with any degree of certainty.
As noted, this is a statement of the obvious, and I'm sure everyone gets it. And I know there's a huge global industry that depends on keeping everyone nervous. I guess my own feeling (as a 3 x a month long haul pax to lots of strange places) is that if we want to get home in one piece, we just have to smile more and grumble less, and accept that this is the time we live in.