How can I report a addon to Blizzard?

[Henceforth-area-52]

@Horace-remulos

I find it interesting that the blacklist mod is allowed to exist.

It is not.
It is against the ToS:

@Kaivax

3. Add-ons must not negatively impact World of Warcraft realms or other players.
   Add-ons will perform no function which, in Blizzard Entertainment’s sole discretion, negatively impacts the performance of the World of Warcraft realms or otherwise negatively affects the game for other players. For example, this includes but is not limited to excessive use of the chat system, unnecessary loading from the hard disk, and slow frame rates.

I have already reported and got many weak auras from WagoIO banned for this and some other addons out of curseforge.
It might take some time until curseforge takes it down, but make sure to report to Blizzard at the e-mail provided in the thread I just linked:

WoWUI@blizzard.com.

They will make sure to ban this addon in game, so people won’t be able to activate and they can’t distribute it even offline.