Social media is mind of a dumb phrase. It's as valid a description of the web as it is anything else.

What sucks isn't social media, it's surveillance media, that is media which requires hoovering up behavioural data to serve content and advertising explicitly to change behaviour. This is the central problem of the platforms: on the one hand they collect behaviour data to better target advertising, on the other they explicitly change behaviour through advertising. Feedback loops of hell ensue.

There's nothing wrong with social media. There's nothing wrong with advertising either (free market + free speech). The risk is when dragnet surveillance couples the two together into a single system which feeds itself.