Exuberant personality, talented, workhorse and often play on the edge will do that. Some people will claim that it's racism and I think that's wrong. Other black players in the league don't get the same treatment. I think this treatment is unjustified. This guy's charismatic and has infinite marketing potential for the sport.
Also, the classless and unrespectful labels he earned from his early years in the NHL managed to follow him for whatever reasons. Some players (let's say Marchand for the sake of the argument) will often use the media to insult and troll. When you read or hear anything from Subban in the media, it's always with respect and humbility.