No, this is not. It is pretty universal on international flights (to the US) these days as they expand the ridiculous behavioral interview program.

Delta does not allow online check-in at a lot of international airports. They will make you go to the check-in counter. Before stepping up to the actual counter, you will be greeted by a "security" contractor. This security contractor has a tablet and will ask you a series of behavioral questions to determine whether or not you are a "risk". If you are, then you will be subject to secondary screening at the gate.

I refuse to play along and answer any questions, so I always get my bagged searched at the gate. Depends entirely on the airport, sometimes it's a quick explosive swab, at others they completely search your bag like it is in the most interesting thing in the world and examine every little thing.

This was all implemented as a "compromise" to the DHS proposal of not allowing laptops in cabin luggage.

I guess you could say it is "SSSS" only in the sense that now everyone gets SSSS-lite treatment at many airports.

Security theater at its absolute finest.

I can't speak for EDI, but more and more airports have this now. I actually haven't flown internationally on Delta in the past year where this isn't the procedure.