Is this considered child neglect? And would you have spoken to to parent in this situation?

I saw a father and his two sons (a 9–10 year old and a 2 year old) and the older kid was basically man handling the toddler, chasing him across the section of the store until he fell down numerous times (there was thick carpeting) until he cried. He also kept hugging him aggressively and frightening him, while getting precariously close to wooden bookshelves. This happened for about 5 minutes, with the Dad having a stupid grin on his face as if it was a cute family moment.

I’m assuming this happens all the time in this family. Unfortunately I succumbed to the bystander effect and didn’t say anything. Even though if I intervened, it probably wouldn’t have done anything helpful, yet I still feel terrible about it and really wish I said something to the effect of “Your toddler can’t even defend himself by your son’s bullying. I really hope this is just a one time thing and that you teach your child not to be a bully.”

Thoughts?