if it were me..when i saw the bigger dog coming down the isle, i would kneel down, say sit, push the wittle bottom down..putting my hand on his head i was say stay good boy that's just fine..in a calming way..if he started to growl. i would give a sharp low no with my voice, and then again reassure that all is fine. and that his behavior is as u want it to be, by sitting and staying in one place..with u by his side not standing, but on the same level so he knows you are in control. Ask the people to move on quicky and not let their dog sniff your puppy because he is just now beginning his socializing skills. U are his mama now, and if he knows that he doens't need to be afraid, then he won't be and the need to growl will be eliminated. I have never had a dog that i couldn't take anywhere. So i can only speak for what i do and what has worked for me. I treat a puppy as a child. I don't allow whining, or pulling me about, they need to know that u are boss so their behavior always cues from yours, not the reverse.