It depends on how badly injured the person/animal is.
I didn't understand your post at first.
Assault has a maximum penalty of 5 years, because assault is the threat of harm.
For example, aiming a gun at someone.
Battery, however, is an actual attack on the person, as in, punching them, which has a maximum sentence of 100 years.
A 100 year sentence is very rare though.
These people did not threaten the dog. They attacked it.
I'm against this petition but that is a flawed argument.