I think there are risks to doing porn, but even in this article, the issues are not always related to the porn itself, but bad passwords leading to account compromise, or linking your family identity to your porn identity.

Understand that "I don't like it" is not a convincing argument to anyone but yourself. Be aware of the consequences, but don't over dramatize it. If you only share the worst case examples, your kids will understand that you are using scare tactics and what you are saying is unlikely. They live in this world and will know plenty of counter examples where nothing bad happened to the person in question.

So, be informed, and be reasonable. Express caution, and concern around linking porn to your "real" identity, and the trouble that this causes people. Discuss things protecting your privacy by avoiding showing your face, house, etc. Don't re-use usernames. A person who is informed on the real dangers of how people get found, will be more likely to think twice before posting a nude.

And if your children are of the female persuasion, it's worth pointing out that women tend to get the brunt of "punishment", while men often are not really affected. Maybe if your children are male, you might not want to mention that, but it's probably good for you to be aware of it.