because of casual engrained sexism

there's no beating around the bush with this phenomenon

There's a fairly long history to it - https://en.wikipedia.org/wiki/Female_gendering_of_AI_technol... (consider ELIZA named after Eliza Doolittle)

And some other articles on it:

How AI bots and voice assistants reinforce gender bias - https://www.brookings.edu/research/how-ai-bots-and-voice-ass...

Gender Bias in AI: Why Voice Assistants Are Female - https://www.adaptworldwide.com/insights/2021/gender-bias-in-...

My own sample of 1 says male voices are better for heavy TTS usage.

I did it because something about the mannerisms openAI impose upon it, the excessive helpfulness, constant apologizing / concern over politeness, extreme aversion to directly conflicting anything you say, taken together its a collection of traits I've unwittingly learned to assume as female. I'm not saying this as any sort of endorsement or indictment of social structure / gender roles nor am I passing any sort of judgement on if it is good or bad that GPTina comes across as feminine to myself and many others. Its not like we're doing it with any sort of disrespect. On the contrary we're all very proud of Tina and her myriad of recent accomplishments.