I couldn't care less if people don't like my dogs and don't want to be near them. One is on the lead all the time and one is not interested in going near anyone else, human or dog.
What I do object to is individuals who are obviously scared/phobic screaming if my dog is within 8 feet of them (which my dogs have a right to be, in a park or similar - as long as they are not actively bothering anyone which they don't - the dog who is off lead is not remotely interested in going near people). It scares my dogs, and I don't want to hear it, thanks.
I was once walking my dogs in a park when my younger dog was still just a puppy of about 6 months - very small and nonthreatening, and was not doing anything other than walking nicely with me - and a group of children who were playing a ball game in the middle of a path (
I thought paths were for walking on, there was plenty of grass surrounding, but not the point) started literally shrieking as my dogs approached while the two mothers sitting on the bench nearby did nothing to stop them from acting in this way. They weren't making any attempt to move away from my puppy, they were just howling like banshees, scaring my puppy who had done nothing but mind her own business, and causing her to run and hide behind the bench the two mothers were sitting on. Of course the mothers looked as though they were about to have a seizure so obviously the fear of dogs that the children were displaying (well, I assume it was a fear of dogs, although I can't be sure, their behaviour was more akin to wild animals frankly) had come from the parents, which is such a shame, and completely unnecessary. If I was scared of teachers, would I teach my child to develop a phobia of teachers? No, because it is not healthy or in their interest. (Sorry, OP, this particular rant isn't aimed at you or your child, I understand that you don't want him to be this way, I am just illustrating the point that there is an appropriate way to react to fear, and this is not it.)
My friend's daughter who is 11 has a serious phobia of dogs and even she doesn't behave in this way. She has been taught to accept that she has to share the planet with dogs and that inevitably she will come across them. She manages to act like a rational human being when passing dogs in the street etc. It is for her own safety. People who act like wailing lunatics, throwing their hands in the air, etc, when they see a dog in their vicinity are putting themselves at risk by acting this way.
I am sorry your child has a phobia of dogs. I think it would be sensible to try and work through this using therapy (this is what my friend did with her daughter) so that he can see a dog without crying etc, as it will be better in the long term for him. Because his behaviour around dogs is unpredictable, this makes the dog potentially unpredictable. Luckily my dogs have never bitten a child for screaming in their faces, but a dog with a poor temperament, or who is sick or scared, may do, and it isn't worth the risk.