Like isn’t that probable cause saying that you did something?
It’s slang nerd
I’d love to meet slang nerd.
Woah! I’m walkin’ here!
more common than you think https://en.wikipedia.org/wiki/Double_negative
different dialects can have different rules about their use
Not everyone is equally educated on grammar. Not everyone cares about using proper grammar.
If you’re asking for a deeper sociological or psychological reason, then grab some books on education disparity, poverty, public schooling, etc.
Grade school grammar is not a proxy for intellect or education. I’ve never read an author who had half the respect for grammar that Chat GPT does.
This occurs in more languages than you think
It’s not ‘people are dumb’ it’s ‘linguistics is dumb’
There are languages (e.g. Spanish) where a double negative is still understood as a negative.
Standard varieties of English aren’t among them, but some dialects are.
The same is also true in German.
Even in Spanish, some double negatives are underestood as negatives, like “I didn’t do anything” (yo no hice nada)