You're not wrong but we can stretch the definition of social media to the point where it's no longer useful. Still, doesn't change the meaning of my original post. Sharing content on your own site, on your own terms and interacting with others directly via email is by far the best replacement to the current situation. At least it is for me.
I think the differentiating factor is a simple one: you interact with people that you would not have known in real life, a global 'two way street'. If it doesn't have that component then it isn't social media.