I live in a quiet soi with 12 soi dogs and one owned dog running about 24 hours a day. Other than the 11.00pm howl and the occassional scuffle between themselves the dogs are harmless, most of them running away from humans, even those of us who see and feed them each day. In 3 years in Thailand the only time I have had problems with dogs they have been owned dogs. Bitten by a lab cross that got out of the gate to the property, attacked by a Rotti that jumped a garden wall to get at me and, most recently, attacked by a collie cross that lives in the next soi as I was cycling by. It is definitely an owner problem if these dogs attack. I have had, trained, and worked with many breeds and 9 times out of 10 it is how the owners train and treat the dogs that leads to them becoming aggressive. And as for the breed being dangerous, my ex wife had a Ppillon that attacked a copper in the UK. Hardly a dangerous breed but when she refused to walk or train it the dog became terrotorial and aggressive towards strangers.
Start by licensing dogs and licensing breeders. Soi dog foundation and other charities to a good job of neutering soi dogs but dog owners should be made to do the same. If you are not a licensed dog breeder your dog doesn't need nuts!