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.
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.