If you say “I’m gonna get a coke” and get a Pepsi, you’d call that wrong, probably, I don’t know where you live
But if you said that in the US South you wouldn’t be using it wrong, that’s how the phrase is used, most people have a common understanding that a “coke” means a soda of any brand, it’s inconsistent
If there’s a substantial enough group of people who have a different and common (as in shared) understanding of a phrase they’re “using wrong”, it starts actually being “used right”, as it successfully communicates a thing
If there’s a contingent of people as large as 30% who understand something completely different by a phrase you’re using, I think that’s not “using it wrong”, that’s it being inconsistent