Well sucking faces on a train would not be accepted, but that's a bit of an extreme example. What I should say is that where I live "french kissing" for a medium period of time on the street is accepted.
Well, yes, I suppose it is as well in the states. I suppose it really depends upon where you are at. If a couple is in a park and they are fawning and doting on one another, or french kissing, no one takes much notice. But if you were in an elevator and just start making out, I think it would tend to either annoy or embarrass some of the passengers.
This reminds me of how there isn't any topless sunbathing in the United States. It's another thing that doesn't cause a bat of an eyelid in a lot of European countries but is considered vulgar (illegal?) in the U.S.
Well, I'm from Miami Beach originally, and it is not taboo there. Not one bats an eyelash there either. There are also specific nude beaches in the San Diego area as well, but it isn't like Miami where it is common. However, comparatively to most everywhere else in the States, yes, it is not only uncommon, but illegal in most cases.
Well, come to think of it, there is of course the Spring Break locations (South Padre island, TX - Daytona Beach, FL - Lake Havasu, AZ - etcetera) where local law enforcement will turn a blind eye to the sheer carnality, if only for a week or so.
I guess in the final analysis, public displays of affection are either tolerated or looked down upon depending on the location and the level of passion being exhibited.
Edited by Nemesis Juggernaut, : edit to add
“I know where I am and who I am. I'm on the brink of disillusionment, on the eve of bitter sweet. I'm perpetually one step away from either collapse or rebirth. I am exactly where I need to be. Either way I go towards rebirth, for a total collapse often brings a rebirth." -Andrew Jaramillo