Here's why Twitter/Facebook/other platforms are publishers. Neither electricity nor phone companies actively curate content, that, is, choose what content will go where and why (like a newspaper, that is, a publisher). Just cause algorithms are involved not really a difference.

Neither do electricity nor phone companies (usually) deliver advertising based on the curation of content and vice versa. Neither do they as companies foster discussion. Etc etc.

In fact, this goes back to a basic confusion. Not even the web is the same as the internet, and social media is certainly not the internet. Neither are apps or platforms. The utility, if there is one, is the internet, the rest is increasingly some equivalent to publishers.

this is before you get to 1 the over-fetishization of content/representations and 2 the out of date characterisation of both media in general and the divisions within it on all sides, based on a media "age" that's now perhaps passing

per McLuhan but also Whitehead, Langer maybe, a lot of media ecology, Lovelace, Deleuze, Hopper, Virilio, Harney, and many many more.