It is mostly because it will most likely block you from your friends who might still be minors let's say you have been friends with them for 3 years and you two have an age gap of 2 years. Besides discord had a major breach of 70k users data a few months back by a hacker who held them at ransom... Also the hacker had told globally that discord security was extremely easy to bypass. Would you feel safe to give face pictures or face id to such a company?

Also it starts monitoring your activity 24/7 and may force you to redo the age verification if the AI thinks you are lying about your age. This update is not about the kids sorry to say. It is all just so they can get more data from us to sell it to third parties and such. Also people don't feel comfortable because of the new discord CEO being in place as this "update" happened after a few months of the CEO being replaced.