There's a bit of TSA misdirection going on in this discussion.

When you ask about "screening", you're asking about physical screening. But when he speaks about "screening", he's probably talking about background checks.

So, yes, the TSO you followed into the airport was "screened" (background checks). And since we know that background checks are absolutely perfect predictors of future behavior, there was no need for him to be "screened" (physical screening).