Here are a few things to consider:
-the woman didn't push pluto. he tripped over the curb that he didn't see.
-after looking at it, it looks like Pluto got ticked off at the kid for some reason. after the running was over, you see him pull on his ear and point at the kid, as if the kid had pulled on Pluto's ear, and probably almost pulled the head off, hence why it ticked the dog off so bad.
-Being a character is a fun, but HARD job to have. I know the characters are supposed to be nice. However, I was the mascot for my high school for a period of time and it can get hot in those things, and it can mess with your head.
-these days there is supposed to be a character attendant with every character to make sure they as well as the public are safe. where was the character attendant?

he/she could have prevented that kid from doing anything.
-where was the kids guardian(s)? I see either gross child neglect or bad parenting for letting their kid get away with doing anything, even giving a cm a hard time. Either way, the parents should be ashamed of themselves.
When I have kids and take them to WDW, I'll tell my kids to be nice to the characters because the characters take time out of their schedule to spend time with their fans and sign autographs. And if my kids do something like pull on them or do anything of that accord, they will get an immediate spanking. Just my two cents.