I can understand the desire to differentiate places like ENWorld from other social medias.
I think when most people think of "Social Media" they think of the big, algorithm driven platforms like FaceBook, X, Instagram, or similar. Platforms that exist for the sole purpose of harvesting our data, maximizing our usage time, and selling ads.
We kind of compartmentalize the more "wholesome" sites like this one, where it's community forward, and the ads are more tertiary.
At the base level though, all of the above listed sites are platforms that aggregate content for people to create, share, discuss, and consume content with other people.
ENWorld is most definitely social media.