Periodic reminder that "alterhuman" means a lot more than "nonhuman", "therian", "otherkin", "fictionkin" and all of those combined.
Alterhumanity is simply the state of not falling within your "societal norm" for humanity or what is considered the "normal human experience". That sounds maybe vague and broad, and that's because it absolutely is.
Is being otherkin or therian alterhuman? Sure! You're also more than welcome in the community. But if you're looking for a term to refer to otherkin, therians, and other people who identify as nonhuman? Well--just say nonhuman!
When writing something addressed to "alterhumans", be it a bunch of questions, or an experience post, or a survey, it should be addressed to alterhumans, not tailored to one specific group. Only explicitly talking about the therian or otherkin experience within an article or questionaire or similar things lends us to wonder why those aren't just labelled as therian/otherkin/nonhuman. That doesn't mean those groups don't belong in alterhuman spaces or tags either--this is simply a nitpick at how things are worded and seem to be sometimes misinformed about what alterhumanity is.
Alterhumanity includes (but isn't limited to):
Otherkin, therians, nonhuman headmates, nonhumans in general
Fictives, fictionkin--including those who identify as human fictional characters, fictionlinkers, fictionhearteds and other fictionfolk.
Factives, factkin, factlinkers, facthearteds and other factfolk.
Otherlinkers and other voluntary identities.
Otherhearteds and people with synpaths and/or hearthomes.
Plural systems of all origins--created, disordered, nondisordered, anything else.
Delusion-based and other neurodivergent and/or disability related identities, largely relating to the above points (such as clinical lycanthropes, systems due to psychosis, etc)
A lot of the above can absolutely include human identifying individuals (or systems). You do not need to be nonhuman at all to be alterhuman. You also don't need to "pick" one or the other--you might be both, or aspecies, or something else entirely. Humans can be included under the alterhuman umbrella, alterhumanity isn't the same thing as nonhumanity.
We've seen the claim that it's dehumanising (not to an individual's own tastes by the way, this was stated as an overall community fact) to be included under the alterhuman label, so more identites that include humans or are human-based need to be "written out". That is alterhumisia as well as nonhumisia and paints alterhumanity as an inherently dehumanising identity. You don't have to use any terms you don't like, but dehumanisation, alterhumanity and nonhumanity are all separate things.
Alterhumanity is as mentioned, having an identity that's alternative to the "societal norm".
Nonhumanity is identifying or the state of being nonhuman.
Dehumanisation is the act of treating a person/group as "less than" human. It is a form of discrimination revolving around the idea that you can even be "less than", and therefore are able to be treated without dignity, moral consideration and empathy. It's the denial of someone's human rights. (Attempt at summing up without going on for 5 paragraphs, please forgive strange phrasing).
Don't confuse them. They are different things. You might not like being referred to as alterhuman or nonhuman, and that's your right! But others including communities you happen to be a part of under that term doesn't strip you of the right to not take on the label itself, nor does it deny you your humanity in any way. You can opt out. Others opting in or being defined in from the start isn't dehumanisation.
And on a quick side note, we also noticed a distinct push to exclude systems from the alterhuman label in recent times or to say they never should have been included. While no one has to use the label if they don't feel it fits--you have to at least acknowledge that plurals were defined in from the beginning and many systems find the term useful and define themselves as alterhuman on the basis of their plurality alone. No one is forcing a label on anyone, but please don't leave systems out of your discussions of alterhumanity by default. Non-alterhuman systems don't need to participate in the community, and alterhuman systems don't need to be defined out of a term that had them in mind at its coining.
The coining post is linked here, for all who would like to read it. We know not everyone has, and we also know terms change over time of course--but the broadness is a huge point of the term itself. Don't make the box smaller. That's the overall point of this post.