Being otherkin, to this group, isn't just about resisting technology or being in touch with nature (though these, and other fantasy and new age elements, still form a large part of otherkin culture) — it's about being marginalized, ignored, laughed at, and oppressed. It's like being transgender. And as this otherkin group has transformed its language and its focus, so too has its scope widened. Otherkin identities can encompass fictional characters. Or nonliving, inanimate objects. Or even multiple identities — some fictional, some animal, all of them occupying a single body. Out of this widening comes new words: cisspecies. Transethnicity. Transablism. Transfat.
Tumblr, which has a huge, passionate social justice community — thousands of people interested in feminism, gay rights, trans rights and other interrelated issues — is a natural fit for this group of otherkin. (Other, similar communities exist on LiveJournal and the TV Tropes message boards.) Like other Tumblr users who are members of marginalized groups, otherkin start their own blogs and write about their identities and the axieties and injustices of daily life (one says she was fired for being otherkin, others talk about coming out to their friends and family). They trade support and sympathy. And they fight with people who don't buy it — more often than not, people who they think should be broadly sympathetic to their goals.
From Otherkin to Transethnicity: Your Field Guide to the Weird World of Tumblr Identity Politics