So earlier some dude posted asking for help with the LUA script for an addon he was making for World of Warcraft. I know it existed. Because I posted in it.

But the topic doesn't exist anymore. And I can't help but think a Mod deleted it...but why? Is it because they thought it was a violation of the rules?

Blizzard has released an API for their in game interface. Custom addons can be created using LUA scripting. These are perfectly legit extensions and in no way violate the Blizzard ToS. The addon's cannot automate anything like movement or attacking. It is purely aesthetics like reskinning your action bars, or combining your 8 bags into one giant bag for easier viewing.

So what gives? Why is that not acceptable for this sub-forum?

It was probably for a private server and he needed help scripting a boss