Interesting that you site none of these "authoritative" sources. Meanwhile, Miriam-Webster, Oxford English Dictionary, Grammarly, the Associated Press, the Chicago Style Guide, and the MLA and APA Style Guides all support the singular they as grammatically correct. I don't doubt that you can find some source here or there that still stubbornly opposes the notion, but the idea that there is anything less than near-consensus on the grammatical correctneas of the singular they is factually wrong. You are wrong.
On another note, justice/oppression/politics have a tremendous impact on language all the time. This should be painfully obvious, at least to anyone living in the US. Just think about what kinds of terms were considered appropriate to refer to certain kinds of people fifty years ago, and how well many of those would play today.
Also, quite frankly, I'm getting a little tired of your condescension and patronizing attitude regarding my personal preference in pronouns.