That's a category error. Fetch is just refers to making a request. POST is the method or the HTTP verb used when making the request. If you're really keen, you could roll your own

  const post = (url) => fetch(url, {method:"POST"})

I read this as OP commenting on the double meaning of the category. In English, “fetch” is a synonym of “GET”, so it’s silly that “fetch” as a category is independent of the HTTP method

That makes sense.

“Most” is doing a lot of heavy lifting here. I use plenty of APIs that are GET

I was thinking server-side where it's probably 90%+ POST. True, client-side a lot different (node the only player client-side, though).

Node was created with first-class native http server and client support. Wrapper libraries can smooth out some rough edges with the underlying api as well as make server-side js (Node) look/work similar to client-side js (Browser).