I don't think Dropbox is listed on the App Store (I doubt it meets the sandboxing restrictions)
Re:How Dropbox Hacks Your Mac
by angry_octet on Saturday September 10, 2016 @09:22PM
(#12471643)
I meant the IOS App Store, not the Mac App Store. But this does highlight why Mac App Store app restrictions exist.
Re blacklisting, I'm referring to Apple's Xprotect (https://www.intego.com/mac-security-blog/topic/xprotect/).
Apple really should kick you from the App Store and blacklist dropbox as malware.