User cannot delete his own topic

I created a Trust Level 1, and this user cannot delete the topics that he created himself. It appears that non-staff users can only delete their replies, but not the topics that they created. Is this by design?

Yes this is by design and always has been. Deleting a topic full of replies is community hostile. Posting a topic then deleting it is griefing. Feel free to search for prior discussion on this.