You're not wrong. @cheetah serves a few functions, she is to inform users of content that may be copied from somewhere else and that isn't always the case. Sometimes it is just similar content. As many sentences that are written on the internet and the nature of certain topics there are only so many ways to say some things such as tech & science terms and concepts.
Lot's of content creators post some of their older content here others get caught with the glitch in the #Dsound app. Even more run contest and curation posts.
Getting a @cheetah comment isn't always a bad thing.
Unfortunately many users don't take the time to read and understand what @cheetah does and while it helps @steemlceaners find plagiarists and copy pasters it really just an informational bot for the community to see and make their own decisions.
My advice to anyone that gets a @cheetah comment in your case is just to reply to her and note that it is a glitch with @dsound.