There’s way more security at an airport than at a shopping center. Malls and grocery stores are fish in a barrel situations

While this is 100% true, there is far less security that most people think. A lot of people still think TSA goons are armed law enforcement. Nope - they aren't armed* and they aren't law enforcement. There are, however Federal Air Marshals that are now part of TSA so those plainclothes people *are in fact armed.

As far as more security - I wouldn't count the regular TSA people since there really should be security to protect us from them molesting and stealing from us. There are local law enforcement usually onsite, which is probably more than in an average mall, and Air Marshals can patrol or help out in between their flights.