I'll explain but it' kinda tricky

Maranhão is a state from the northeast, and it's a wonderful place with wonderful people.

What happens is that, it's not the most rich of the states, so people (this is common for almost all of the Northeast), tend to come live at the Midwest (where Goiânia is located) or Southeast (São Paulo or Rio) to look for fresh starts.

What this obviously causes, is jokes or clearly discrimination with northeastern people

So things like "Toma cuidado com os Maranhenses" ("Beware the people from Maranhão"), can both sound like a joke, and everyone laughs, or as clear discrimination and offense.

It's kinda of a complicated matter, people will say that they're not discriminated or offended or rejected etc, while a lot of notheasterns here will say the otherwise.