It could be seen as a "user interface" in some sense, in that there is no other obvious way to integrate all the things a human body (or any other body) does when it is continuously active. We could view ourselves as something other than "consciousness", but that is the way in which we construct any knowledge we possess of the world. Strictly speak, "we" don't have any existence as ourselves, and "I" don't have any inherently shared consciousness with anyone else. If I did, I would be a very different entity. Shared consciousness would be some form of telepathy basically.
Consciousness or "the self" is not constrained to the body or a strictly biopolitical definition. We are what we eat, the tools we use, the communications we have with others which allow for any language. We are not intimately tied to anything external to our body in the way the body's functions are integrated. But, we can view limbs or parts of the body as external. There is no identifiable "center" of consciousness like the brain, if that's what you are thinking, that is inherently what "consciousness" is. Without any of our tools, humans would just be slightly more advanced apes. We only are what we are because we live in a society where language and tool use are ubiquitous, to the point where without that we would barely be recognizable. Said tools and language in many ways modify us during life, and affected human development compared to what we were before tool use developed to anything like the extent we practiced it in any period of civilization. That process didn't end - we are still changing, and quite profoundly, up to today.
So much of this stupidity is about defending a conceit about "humanism" that is rooted in biopolitics, which is intended to destroy concepts of political equality, spiritual universalism where all men were equal before God, and things that are hostile to a social order that emphasizes political and social inequality as much as it can. In a political or spiritual sense, humans are remarkably similar in their basic functions, and humans haven't changed significantly from what they were thousands of years ago in that regard. In abilities and how humans live, we are barely recognizable from someone 3000 or 4000 years ago. Someone in Roman times would be far more recognizable, and they noted their distinction from peoples who were barbariansPost too long. Click here to view the full text.