Richard’s response here pretty much covers it all, I can add a bit here which is more or less repeating Richard’s reply using different words.
Discourse can be used in compliant ways with respect to the laws available, but the software itself isn’t compliant or non-compliant. If you host Discourse for users covered by Australis’s law or for instance GDPR, you’ll need to do so in a compliant way.
And as Richard pointed out, we’ve spent quite a bit of time making sure we provide you with all the necessary tools to be able to do it easily (user cancellation, user anonymization, etc).
For more information on this, please see our Security brief | Discourse - Civilized Discussion for general information and also Privacy policy | Discourse - Civilized Discussion for specific details.