There tend to be many schools of thought here. One school is that screening should do nothing more than and x-ray and WTMD and stop nothing but guns, bombs, knives and other obvious single-usage weapons that are a threat to the aircraft. Such folks tend not to like it when TSA turns pax in for cash, drugs, or other activity that may be suspicious but is not a threat to the aircraft. (Personally I despise how carrying cash can be deemed suspicious and law-enforcement can seize cash with little/no due process. I personally don't carry much cash but I should have the choice to do so if I want.) An example from this school of thought would be people who wouldn't mind sitting next to a known terrorist (even Osama himself) as long as effective security made sure he had no weapons.

Another school of thought would like security to do more behavioral profiling of passengers, ask questions to determine character/intention, etc. rather than focusing exclusively on baggage. They would argue that bad people are the theat, not the bad items. For example, a law-abiding pax with a giant knife is no threat to the aircraft if he doesn't plan to commit a crime.

Both have a good point. But there's probably not a whole lot of overlap between these two schools except that both have complaints about how things are done now.

As an aside, in spite of occasional complaints about impractical posters calling for the end of all screening, there really doesn't seem to be much of a "no screening whatsoever" school here.