It finally happened

To the OP - we pathetic humans don't understand what dogs are saying. We can read their body language if we're astute, but there ARE occasions when a dog is strutting out and saying "I'm going to take you out, Buster - then I'm going to chew up your stupid owner, too". So of course, our normally-friendly dog steps in to protect us from a threat.

And I agree with everyone else - dogs don't need "friends", especially when they're leashed to their owners and might be picking up vibes from them, too. I like the "ebola" comment - I'll have to remember that....LOL!