I neglected to post this yesterday. Unfortunately attacks by dogs are not uncommon - many of the dogs themselves have been abandoned or used to be fed and are now left to fend for themselves. These dogs then join packs and it is really when they are in packs that they may attack.
While I really do sympathise with the caregivers who are losing cats, I fear it may go down a dangerous slippery slope. If people start complaining that cats are killing birds next, then are they the next ones to get rounded up and killed? During SARS, that was the argument used - that cat might cause disease (which could harm people - an even more untenable position for the cats) and hence this was the rationale behind rounding up and killing them.
There are no easy answers to this - when I spoke to Action for Singapore Dogs about attacks they suggested trying to break up the pack by scaring the pack leader off. When the alpha male runs, the rest of the pack will disintergrate The only successful case that I know of when the dogs didn't come back was when a group of caregivers stood guard at night - when the dogs approached, they went down with waterguns and pots and pans and make such a racket that the dogs were scared of.
I do realise it is a difficult decision for the caregivers though and they must be desperate after seeing their cats killed. It's a no-win situation.