Brooklyn Nets star Kyrie Irving made headlines when he recently pleaded to Boston Celtics fans to not display any “subtle racism,” among other things, when he returns to TD Garden for Game 3 on Friday night. Celtics president Danny Ainge responded to Irving's remarks and effectively called BS, saying he has never heard anything like that from his players in his 26 years in Boston.

Well, Celtics guard and former Irving teammate Marcus Smart just gave his two cents on the matter, and his comments back Irving:

Racism is “sad and sickening” no matter the circumstances, but it has to sting even worse when you get it from your home fans. Boston isn't particularly unique when it comes to awful fan behavior like this, but there have been a good amount of complaints about the fans there (and not just Celtics fans).

Smart's comments come after an especially ugly day for NBA fans. Supporters in Philadelphia, New York and Utah were all just banned from games because of their reprehensible behavior. A Sixers fan got the boot for dumping popcorn on Russell Westbrook's head as he walked to the locker room after an injury and a Knicks one was banned for spitting on Trae Young. A group of Jazz fans were also banned for heckling Ja Morant's family.

Smart is sick of seeing this kind of stuff happen:

Irving and the Nets will not be getting a friendly welcome in Boston in Game 3. Plenty of Celtics fans are still upset with how the Irving acquisition worked out, and they're going to let him hear about that disappointment throughout the game.

Still, while it's okay for supporters to boo and talk some trash, the physical actions we saw on Tuesday and racism are unacceptable. There's a line that shouldn't be crossed, and these fans crossed it.