Is it mean...hell yes. He could easily take it as bullying.
Bullying is defined (taken via http://www.stopbullying.gov)
as An Imbalance of Power: Kids who bully use their power—such as physical strength, access to embarrassing information, or popularity—to control or harm others. Power imbalances can change over time and in different situations, even if they involve the same people.
Repetition: Bullying behaviors happen more than once or have the potential to happen more than once.
Bullying includes actions such as making threats, spreading rumors, attacking someone physically or verbally, and excluding someone from a group on purpose.
ETA: I would speak to the parents...you have that option. I cannot/am not allowed to speak the parents of my daughters bully. Due to confidentiality...let's save the bully not the victim...is how I see our situation.
ETA: I have issues with people saying it's typical boy behavior...ours started out as "typical boy behavior" chasing a girl on the playground...next thing you know he chokes her three times. I firmly believe "typical behavior" is out the door and no longer should be used as an excuse.