As regards kicking a dog – it shouldn't have to come to that. A responsible dog owner will have his/her dog under control at all times. If one is off the lead and comes near my kids at pace (which does happen occasionally), then I reserve the right to kick it away. If the owner wants to kick me for doing so then that's a bridge I'm willing to cross.
Having said that, I actually like dogs (well behaved ones). Never want to own one however, because I don't have the lifestyle to look after them properly and hate dog poop. Also, if a dog owner gets fed up with my kids running around in restaurants, they would be correct to moan as that too is pretty unreasonable.
I'd like to think most people understand (macho posturing aside) that there is a difference between kicking/slapping a dog and a child…
Although these discussions are always heated, there isn't much between the arguments – sensible/considerate dog owners are rarely a menace. However, the completely irrational defence that "my dog could never be involved" in a situation like the OP mentions is ludicrous.