I bet the dogs that bark are all tide up on linen lines, don´t look at the dogs, they may take your stare as a challenge.
I imagine a lot of these dogs are bored out of their minds having to stay put all day tied to the caravan/motorhome, how would kids behave if they were treated so, better still how would you feel.
Dogs should be kept active in body and mind. Every one loves their dog, thats not enough, they have to be taught to behave and basic training is often missing.
We avoid camp sites when possible, if we do HAVE to go to one we would always choose a spot away from the busy area even though our dogs have always been well behaved, as you say, not everyone likes dogs and some are afraid of them,
It would be an idea me thinks, if sites that allowed dogs had a separate section with a play area for them. If there was such an area for caravaners/motorhomes those that don´t like dogs could stay away from that area.
You are quite correct, its not the dogs fault, they think what they are doing is the right thing, its the owners at fault for not teaching them otherwise.
Mind you, if you came to our van you would be barked at as thats how Shade greets everybody, even us