It's interesting to see the parallels between the different communities. I only have some passing knowledge about plurals from many years ago when I learned about tulpas. I definitely do recognize the "roleplaying in their mind" aspect, though, as that was the reason that made me bail pretty quickly. People were talking about not just conversing with their tulpas, but also having outright epic battles with control over their body at stake. There was romance, action and drama. It was wild.
The way I like to look at this phenomenon is that labels and people will always change and that it isn't up to us to determine who's "valid." At the end of the day, that's up to the community as a whole and we, as individuals, can't change that.
It does suck for people who are part of a community, only to have it slip away from under their feet and turn into something they don't identify with anymore. Not only that, artifacts from before — the culture and terms that helped us find each other — are overwritten with new meanings, so you can't even reliably find people who share the same values.
I was thinking about using the therian label for myself for a while, even though I don't feel like part of the community. In fact, during that time I made that custom emoji you're using.
I eventually decided not to and instead let my "vibes" speak for themselves. I think it works pretty well since I do have quite a few therian followers I'll happily interact with.
Don't take this as me pressuring you to stop using the label, though!