Slang is dependent on many factors. Region, language, age range.

Just because someone in Boston is calling their city "The Hub" doesn't mean anyone outside the city is referring to it like that.

It would be asinine to try and "correct" people outside of the area and enforcing language is ineffectual.

You want to get into a big debate over words? How about the fact that other countries don't even have the respect to call the other countries what they call themselves. There is no Rome, Italy. It's Roma, Italia. Same with Lisbon, Portugal. The people of the city call it Lisboa. But I'd be an asshole to try and make you call it Italia when you've been calling it Italy your whole life.

There's a difference between prescriptivism (a word you seem proud to know and use) and acknowledging a regional slang but not choosing to adopt it.

I don't care what word people use for something. If I have a word I use already I'm most likely going to continue using it, especially when the slang word has to be explained to everyone that isn't in your circle.