From https://www.theverge.com/news/797051/discord-government-ids-leaked-data-breach :
Of the accounts impacted globally, we have identified approximately 70,000 users that may have had government-ID photos exposed, which our vendor used to review age-related appeals.
So they only demand your ID if they've somehow decided that you're underage and you want to appeal that.
Some of the terms that have been coined to describe stuff related to AI are just so funny.
"Prompt injection attack", also known as... asking nicely for the chatbot to do a thing.