My kid's a brute

Today at daycare, I put baby guy down on the play mats with the other infants. They were all sitting there playing with toys.
All of a sudden, Baby guy just reaches over and whops the kid next to him, on the head. He was pulling hair too!
I pulled his arm away and said 'No'. I'm pretty sure he didn't understand what he was doing was wrong. He is only 7 months old...

I asked the teacher if they noticed him doing that alot and they said 'Oh yeah!'
The assistant director was in the infant room and she chimes in with, 'Yeah, Baby guy is going to be a bully when he grows up' They were all joking, not serious at all, but I was alittle distressed to think my kid is being a brute and grabbing and smacking the other kids.

I see little notes in my future, little notes pinned to his chest when I pick him up from daycare, little notes that read 'I hit' or 'I bite'. Is this what I have to look forward to?

Mom