That is horrible, but it was so good that you were there to help out!

Animal cruelty like this will continue to happen, if regular citizens don't speak up against it! Instead of just being angry, use that anger productively by petitioning your local governments to make stricter laws to protect animals.

Here are some resources from Stray Pet Advocacy to help you take action:

Animal Cruelty Laws - U.S.

Resources to lobby against animal cruelty

And here is a direct link for Canadians:

Canadian Animal Cruelty Laws and Info