While it is certainly possible to make a weapon from items purchased beyond airport security, some people lack the creativity or motivation to do so. Bad idea. Sometimes it is an innocent oversight, the item confiscated and you are on your way (to be sold to fund this statist monstrocity, if they aren’t pocketed by TSA agents themselves). But some people go to great lengths to hide dangerous items. Like in an enchilada.
Gizmodo has complied some of the most bizarre, extreme, and sometimes humorous items confiscated by the TSA last year. My vote for meat slicer. The turkey sandwich in Coach is never sliced quite thinly enough.