Home alone question?

So in the movie "Home Alone", Johnny (the gangster) says "too bad Acey ain't in charge no more".

What he really meant was "too bad Acey ain't in charge anymore"

Lots of people talk double negatives (even if they graduated college).

So even though they aren't necessarily stupid or dumb, why do they talk double negatives like that?

2017-04-11T00:37:33.809Z