I was, and still am to an extent, in quite a vengeful and vindictive mood.
As a moderator, you could point out there is already a topic on this and even provide a link. Its a new user so they might have even click the wrong link by mistake and posted a new topic instead of replying. You could take the option that might encourage this new user to come back again (part of the job you signed up for). Instead you just want to flex your moderator powers and delete the entire topic.