To be honest, I would probably be the person telling kids to never share accurate information about yourself online. Granted this is bad advice if you're convincing kids to not play mature games (which should be a whole separate conversation in itself) but I think there's a huge looming issue with online presence.
There's a lot of kids leaving a huge amount of information about them online because of the internet storing almost everything they do. They link every account or every detail to themselves in real life, making it easy for people and companies to gather a ton of free data. Some of which might be dangerous to their future careers.
Which is why I feel telling kids not to share things online is like abstinence-only sex ed. As an adult, you have the wisdom and self-restraint to practice abstinence. Teenagers have neither of those. But they do have brains and bodies that put them at risk for STDs or pregnancy. It's foolish to make them take a gamble that their physiology has stacked the deck against them.
Socializing with your peers is as natural as sex. We grew up where online communication was either non-existent or niche enough that we don't feel it's necessary for socialization. But teenagers today have been exposed to the internet since birth. To them not participating in social networks is as absurd as being constantly online is uncomfortable to the older generation. Or it's like telling a teenager to ignore their sexual desire. It's not going to happen.
So teaching kids how to be safe online while still participating is the practical thing to do. And it's important to give them tools and knowledge that makes it possible for them succeed in protecting themselves.
When I think about it that way, I question my own standing in the privacy debate. I often point out how older people seem out-of-touch with how technology works. Well I don't participate in a lot of social platforms. Why should I be listened to about what is appropriate for those companies? I can say what I want for myself, but that isn't necessarily helpful for people who have a different lifestyle than I do. Does being too severe an advocate for privacy, and demonizing social media companies make me like to the old church lady saying that giving out condoms in school is evil?
I don't think that is a quite accurate comparison. Telling kids to not share things online and telling them to minimize details that identify them are two quite different things. The closest analog to your abstinence comparison would be telling them to outright avoid or refuse to use social media.
The easiest way to explain to them how to properly be safe online is to ask them 'what would your parents or teachers find if they looked up your username? if they started googling details about you?'. They may not care what their friends might find, but when you rope in family and teachers finding more personal details that is a great way to get them more invested in maintaining their privacy.
There's a lot of kids leaving a huge amount of information about them online because of the internet storing almost everything they do. They link every account or every detail to themselves in real life, making it easy for people and companies to gather a ton of free data. Some of which might be dangerous to their future careers.