They most likely aren't but when it comes to matters of war its best to prepare for the worst while hoping for the best.
Sweden has always been against joining NATO.
It was deep rooted in the social democrats and even among conservatives.
It has been discussed for years but there has never been a majority for it so Sweden has been outside.
The turning point that even got the left to want to join NATO was the invasion of Ukraine. Suddenly the war came close and it showed that Russia indeed is still a potential threat.
Just for fun and this from before Sweden even applied to join NATO.
2013, Russia sends bombers towards Sweden and train a strike against Sweden.
2013/2014 Russia (suspected but who else) sends drones over Swedens military exerciser. During a navel exercise Russian spy ships are all over.
Back then the military said "iz normal".
It was also not unusual to see big, well trained crew cut people out in the woods on mushroom hunt during military exercises ( yes pretty much confirmed Russians) .
I cant count the numbers of "tourist" from Russia, Belarus that has been caught taking pictures at military installations over the years.
Nothing has changed with Sweden applying to NATO more than Russia is bitching more in media and a few cyber attacks.
Sweden has always had a lot of issues with the Russian military, but imo after the wall fell decided to be naive and also close their eyes.
Russia is not Soviet and the cold war is over so there will be no real wars anymore. Well they were wrong.
And just for fun.
This is what the Swedish defense forces writes on their web site
"The risk of an armed attack against Sweden is currently assessed as low."