Animal Issues

I have been upbraided for sitting on the fence on animal issues. And yes, I know, I'm just another soppy ex-pat who should worry more about people's woes than animals woes.
Nonetheless, I continue:
I just heard tonight about a friend of a friend living nearby whose wonderful pet dog - well-trained, well-behaved, was murdered in it's own garden with poisoned meat.
I have also seen on a closed group for the area where I live educated, professional Egyptians advocating the shooting or poisoning of dogs who are just barking - nothing more.
Now, I know barking dogs can be annoying, but this murdered pet dog was not much of a barker. And in any case is there not a better solution than murder?
Can someone please explain the justification for this?
I do not buy at all the argument I often hear made that "you foreigners should worry about the treatment of people here not the animals".
In what way does cruelty to animals advance the condition of the people here?
In my view, by learning to treat those animals who are dependent on us kindly, (and those creatures like donkeys who actually help people survive with their businesses) this would begin to permeat the society and encourage better treatment of people all round. Ill-treatment of animals is symptomatic of a sickness in society.
Now before you all jump on top of me, I am not a vegetarian and I accept that makes me a hypocrite in terms of that. However, until the time comes when an animal 'must' be killed - for whatever reason is deemed necessary - it should be treated kindly.
I have seen photos and videos in the past two days of some horrific sights of animals being kept in very poor conditions in the run up to Eid, and of animals who have not been killed quickly suffering tortuous deaths.
About a year or so ago, I was walking down Haram St with a friend when we witnessed a yellow taxi run into a horse pulling a cart. The horse was staggering about bleeding profusely from its chest while the guys were arguing with the taxi driver. The poor thing was driven off down a side-street STILL with it's cart on and two guys sat on the cart as WELL and started whipping it!! My god that was barbaric.
How does THIS improve the lot of the people in society?
How does CRUELTY to animals improve the PEOPLE? It doesn't. Full stop.
How does killing painfully a well-behaved non-dangerous pet improve the PEOPLE? It doesn't. Full stop.
It is not part of Islam - I am told that the Koran explicitly requires animals to be treated well. So what, pray, is the reason?
And yes, I hereby fully acknowledge that cruelty to animals exists in all corners of the globe including little old Blighty. However, when it happens in Britain, at least the people have enough shame to do it undercover of darkness, here there is no shame in it and having seen the random acts of violence against cats, dogs, goats, donkeys all around, we see it in all it's glory.
And yes, I know we have our own issues with battery farming etc in the West. And yes I know there are moral questions raised over the concept of vegetarianism in societies where there is limited agricultural land - noone's perfect when it comes to food production. However, I am mainly focused on the point of wanton violence and cruelty to animals here.

(I will add links and tags later - I am doing a project right now til Monday night!)