Found at Dairy Queen

That someone would be me, except I'd feel bad because they spent a lot of effort making that sign

Found the racist.

African American English (AAE) is a legitimate dialect of English, just like what you deem “proper English” and it is only looked down upon because it’s historically a black thing in the USA, as opposed to the dialect used in traditionally more affluent white communities. So yes, you are racist- though your use of the term “ghetto rat thug” demonstrates that anyway.

You seem to have a lot of rage and violence in you. While I agree respect should be mutual, them not speaking "improper" English is no reason to insult them and get physical with the manager. I understand you may have a recent bad experience but this type of reaction is unhealthy for everyone.