Just looked it up because I too was unsure of this. There is a Wall’s meats, but they are no longer related. Unilever owns Wall’s ice cream but they sold off Wall’s meats in 1994. The logos are different and the meats one only operates in the UK. So this map is useless for avoiding dodgy meatballs.
I assume it is the racial slur originally directed at Pakistanis but is now used against all brown people because racists can’t tell the difference. Not that it would make a difference if they could. Racists gonna racist.