Let me preface this by first saying I agree that dogs should generally not be allowed in food serving establishments because their hair goes everywhere and nobody likes eating dog hair.
With that said though, I have never once seen my dog lick his own butt. What on earth are other people's dogs doing?! The closest my dog has gotten to licking his butt is licking around his genitalia, which I grant you is unclean as well, but he's fluffy and keeps the hair between his legs clean and un-matted. But butt licking?!
Now here's where I get down voted to hell, but I have to play devil's advocate lol. I would argue that kids are a MUCH larger vector of bacteria and viruses that are of concern to the average adult human than any dog. Dogs are gross, sure, but I'll take a lick from a strange dog over a strange toddler's sticky hands on me!
We should keep dogs out of food places, but mostly cause hair and allergies - if we're going to ban beings due to their gross factor though that list should be much longer (toddlers, homeless, anyone that didn't wash their hands after using the restroom...)
A lot of Europe is like this and I think part of the difference is social expectation with dogs. Because it's more normal for dogs to go places, and less normal to have private yards at your home for your dog to spend time in, people in Europe tend to spend more time training their dogs to be good members of society because they basically have to. If you have to walk your dog multiple times a day for potty instead of letting it into the back yard, you're probably more likely to make sure your dog is leash trained properly.
I also think the USA (and Canada to some extent as you've kind of adopted many of our values, for good or ill) are more individualistic than many European countries. In America we train our pets because WE want them trained, not because of societal expectations about dog ownership. It's truly telling when you walk a dog that is properly leash trained and get compliments about how well trained your dog is. That a dog can walk on leash without pulling is the exception, not the norm. (This happened yesterday to me, just walking around a park path.) It's depressing. American individualism insists, "I don't need to train my dog, he's perfect being the cute little terrorist that he is, and if you don't like it, that's your problem." As a result, dogs aren't allowed most places in the US because entitled dog owners are the norm, not the minority. I love dogs, and I love taking my dog places, but if I owned a business of any kind I wouldn't allow dogs because it's not worth the headache here.