if the roles were reversed - if AnarchoNina were the one who falsely accused a cis girl of something and then admitted it - she'd have a mob of people calling for Accountability (tm) and a "liar" albatross hanging around her neck indefinitely.
instead, the cis girl is being lauded for her "bravery" in telling the truth - even though she didn't even really apologize to Nina - and Nina will have to live with the accusations indefinitely even though they've been thoroughly disproven.
this is transmisogyny in a nutshell.