Buddy CGC & Help Needed

Well we did it Buddy got his CGC the evaluator said she really liked him & his temperament.
The night before had to throw away 2 of Buddys toys since he chew them up,told him if he got his CGC I would buy him a new toy. On the way home stopped at Pets Mart looked around he was petted by a few people and a kid.Did not see what I was looking for something very sturdy for jaws to chew on. Petco right down the street??? so stopped there finely found something I hoped would last 2 days or so on the way out. A couple stopped to ask about Buddy I was standing there talking to them. About 5 teenagers stopped the couple left and the teenagers started asking about Buddy. I asked them not to crowed around him he was not use to that, one asked if he could pet Buddy I said come up slow with the back of your hand out so he could smell your hand. The kid sat down and was petting Buddy all of a sudden Buddy barked at the kid. I do not know if one of them was staring at him or not I slowly backed Buddy back Buddy barked again. Of course the other boys were telling the one kid that petted Buddy he's going to bite your face off man. I said we had better go slowly walked Buddy to the car & left.
My sister use to have a Rottie told me that morning I should never let anyone pet my dog????She said Buddy would not be protective if I let everyone pet him.
With my Bouviers I let everyone pet them I always thought it gave a dog confidence am I wrong with Buddy he is my first Dobe????
Sorry this is so long but now am confused.
Patches Mom
I did not give Buddy a corection for barking I would rather have him bark than bite.