Coddled wouldn't make you rude. Being exposed to too much internet would make you rude. If you look at the default sidebar in Youtube it's a shitshow.
People outside America are exposed to the internet too, and aren't nearly as rude as modern Americans. Personally, I think the modern rudeness is due to something unique about American culture.
The American Dream curdled into misplaced entitlement and overbearing arrogance.
> and aren't nearly as rude as modern Americans
You haven't been in Russia or post-USSR.
We probably live in different places because I haven't found people to be all that rude where I've lived (cities), but America is huge and has hundreds of different cultures so I'm sure there are some where rudeness is more prevalent.