Could it be that these forums are separated or that they are been described as other networks not directly to be called a social networks?
The online crypto forums are way different than any social network. Crypo forums are meant to give information about crypto currencies where users can be part of discussions, and in such discussions, they share their insights about different topics mostly related to cryptocurrencies.
In social media these days people go only to have some type of entertainment, while on crypto forums you'll meet many intelligent people who share their valuable knowledge to others in the form of posts.
Social media is more or less considered as waste of ones time while the crypto forums are more likely considered as utilization of someone's time in something good. Those members who are part of crypto forums know very well that those forums are different than social media platforms.