Two things are true at once
(1) Upbringing has an enormous impact on agression in dogs. To the point it actually can be a stronger variable in the prediction than breed.
(2) Some breeds still have stronger tendencies towards agression.
But I agree with this sign’s main point. Banning pitbulls won’t stop the agressive dogs problem. Because the kind of people who usually buy pitbulls raise dogs to be agressive.