In your situation you had every right to defend yourself ! the lab was running loose, if he was thazt close to you, and you smaller yorkie you had every right to use force to get the dog away from you! Too bad the Other dog owner could not see it thta way... Than for it to happen two other times

And for them man to make a threatening , remark to you , about your tiny dog? whay the hell? Id be LIVID! These are the times I would love to have a B/F or husband with me to take care of these type of idiots ... Give them a good shake down. Stupid people always are saying and doing the most stupid things. This is a perfect example.
I am glad your Dog was unharmed and you were safe too. PLease , if you can, don't go walking alone with your dogs. I would take along either your husband if you are married, or B/f or a male friend, maybe brother, male cousin or a man just for safety purposes.