I was in many of them, one of the most impressive was "the 5-star hotel" with a hall so big that you could calibrate tank-cannons and in another "bunker/fortress" you could "throw" out f-18 fighter-jets.
To hijack your comment: all of these type of bunkers mentioned in the article are decommissioned as they don't match the modern military doctrine. The majority of these bunkers are artillery and anti-tank bunkers built during the cold war (some during WWII) to play a decisive role in large tank battles.
The article confuses this, as there were some plans in actually deconstructing them which however turned out to be too expensive. So virtually all of these bunkers were indeed decommissioned and most also declassified in the last 10 years (some turned into a museum e.g. a WWII bunker https://www.crestawald.ch/). Others, such as the Castello mentioned by /u/nix23 are used as temporary barracks for troops, but don't have an actual defensive function any more.
Yes, the very pictures used in the article are evidence that the bunkers are decommissioned. Tourists who took pictures like that used to get a stern talking-to and their pictures would get confiscated.
Before viewing the picture, I was thinking they had hidden a whole base in a fake Four Seasons building in Zurich or something like that. After all the other camouflage, I wouldn't have put it past them.
Edit: BTW that the entrance of the 5-Star:
https://upload.wikimedia.org/wikipedia/commons/thumb/6/63/Me...
The plate is for making fun of new recruits because it's the opposite of a "5-Star" and for sure not a "Hotel"