Is this Haram in Islam?

Now I am no muslim, an Atheist in fact. However, I recall reading in the Quran a page about a man getting water for a thirsty dog from a well. An in this it was seen as even though dog's are "unclean" they must still be treated with respect. My question is why do many Muslims hurt and kill dogs and pigs(at least where I am from I notice this). The other day I saw 4 Muslim guys throwing rocks at a dog. Also there is a video on youtube( I will not post it, as it is horrific) with m murder of pigs in egypt during the swine flu epidemic. You can simply look it up by looking up Egypt pig cruelty on youtube(note it is cruel). What are their punishments for killing and torturing these animals?! Will your Allah forgive them? Also this question may be void on the part of the man and the well, it may have been from another religious text I had read this from! If it is from another text then what is your opinion on this cruelty! Also please do not think I am saying only Muslims torture and kill these animals, that would be plain stupid!