Don't be so sure your experience matches everyone else's. The 'we' you mentioned does not include me.
I will add all my work contacts on LinkedIn but I will only add a few (about 5%) on FB; ones who I socialise with outside of work.
The FB office makes me feel anxious just looking at it (the noise and the distractions) whereas that Spotify office looks calming and a place where I could concentrate and get some real work done (just look at the white wall with the patterned lines!).