It was a customs, not immigration. Since it's a European airport, there's no immigration for the Schengen area. You can backpedal from the baggage claim area to anywhere in the transit area. This isn't a huge scandal, it's no big deal. There's a trade-off between "security" and practical considerations. Years ago, I occasionally needed to visit various facilities on the apron in that airport, and I would take either my car (which was registered with the airport authority, properly authorized, and had a sticker to enter), or my motorbike (which didn't have a sticker and wasn't registered because that wasn't needed for motorbikes)...4-5am in the dark, the first 3 times someone ventured out of their booth to check my badge (but there was no way they could see my face inside the helmet), after that I was usually just waved through. But to make the process more secure, there were double gates, one opened, I drive inside, it closes behind me, and then the next one opened. Someone had thought that out, to prevent unauthorized entries
Was my car or motorbike ever checked for anything...no. Did I sometimes drive on sightseeing trips around the airport for no particular reason...yes. Did I have a radio...no. Did I cross runways...yes. Had anyone told me how/where to drive, or not...no. Did we have football tournaments next to the runway, with a barbecue and copious amounts of various fluids...yes. Did some people drive home slightly inebriated (definitely above the 0/00 limit for the airport)...yes. Did the police bother them...no, they participated in the football tournament.
My point is just that confiscating yoghurts and water bottles is mostly a theater, a show, to make people feel "secure". Airport security is...mostly an illusion. Exactly as PM said.