In the US, pitbulls are specifically associated with the black and hispanic communities, so when someone talks about pitbulls being "inherently" violent dogs, it's usually not a big leap for that person to then imply that the "owners" ( ) are inherently violent people.

It threw me for a loop the first time I heard it too, since like a lot of US racism, it's so pointlessly buried in seemingly unrelated stuff, but it is apparently pretty common over there for anti-pitbull sentiment to be more anti-pitbull owner sentiment disguised with a literal dog whistle.