There’s actually a footnote in the article about that!

I’m using  LGBTQIA2S+ as a shorthand for lesbian, gay, gender non-conforming, genderqueer, bi, trans, queer, intersex, asexual, agender,  two-sprit, and others who are not straight, cis, and heteronormative.  Julia Serrano’s trans, gender, sexuality, and activism glossary has definitions for most of terms, although resources like OACAS Library Guides’ Two-spirit identities page go into a lot more detail. Serrano also discusses the tensions between ever-growing and always incomplete acronyms and more abstract terms like “gender and sexual minorities”. There’s a Mastodon instance called lgbtqia.space, and Indigenous people are often overlooked in the fediverse, so I decided to go with the acronym despite its problems.