There are always exceptions to the rule, but there is still a rule. Asking a like question in the U.S. creates uncomfortable reactions, and usually denial that classifying people or countries or ... is not possible!, as you notice in reply to your question; and this is similar at Academia SE.
That all said, I've studied in Germany, France, and the U.S., and spent about half my life in both Germany and the U.S. By and large, all your original questions should be answered "Yes, yes, yes, and yes."
The main reason lies probably in rules that apply in most colleges - you are held to live in university housing, while sharing a room with a stranger for a year or two, in many cases hundreds or thousands of miles away from your hometown. Even when attending universities that, for space reasons, can't have housing on campus (e.g., Columbia in Manhattan), you will usually choose (if only for rent price reasons) a university provided off-campus dormitory type facility. This would have been terrifying for young, shy me, but has some very good consequences in that, by and large, Americans learn to deal with imperfect living accommodations, and to get along with people you have little in common with (my first room-mate was just back from a Mormon mission). Even when I lived in a dormitory at my undergrad alma mater, I had no room-mate, and close to no contact to the other dormitory residents.
There is also a tendency to use college years as the years you go craaaaaaaazy, which is accommodated by the many campus universities which often look like a large park (google Berkeley, or CalTech, say). I've seen a guy run around campus naked, covered in peanut butter head to toes, as part of his campaign to become the football mascot; that mascot (costume) was 'kidnapped' by the rival university (which led to some pompous administrative reactions); one day each year Freshmen caught in a particular spot were supposed to be kissed; and the school band occasionally mooned the opposing team, and performed other 'look how crazy we are' acts. Things have. I think, gotten more Puritan in recent years - I am fairly sure the weird annual kissing tradition stopped. But it existed as recently as about 10 years ago. As you'll know from your campus, that is a far cry from typical European experiences. My undergrad campus, as an 18th century castle built to resemble Versailles, had ample lawns, and a good amount of parties; but the events mobilizing students were the frequent political demonstrations which pulled tens of thousands of students to the castle and the surrounding streets.
Finally, giving a good, entertaining lecture is valued much higher in the States. This is a good thing: all the professors that truly impressed me I met in the U.S. As part of this, lecturing outside happens, but is not common. The world is getting smaller every year though: Europeans teach in the U.S., then go back to Europe - and vice versa; and the Information Age removed barriers that used to be high. So obviously, the stiff Dr. Unrath no longer teaches in Germany either, and I've had classes outdoors there too.