It's just culture. They don't mean to be rude. I know it's hard to understand why they do it or where they come from but it's just culture.
It's not just culture, its a function of EXTREME competition for everything.
The USA doesn't really have any of this kind of competition because the country has had a large resource

opulation ratio.
However, in countries such as China or Asia, you are/were always fighting for everything. This kind of behavior is mostly from the older generation, but even in younger generation, you're competing with thousands of people for the same thing. Every single possible advantage is taken. This isn't like fighting for disaster aid relief or anything, this is a country where if you don't fight others, you don't get anything at all and can't survive. If you get cut in line, its YOUR fault for being slow/lazy/unattentive. The person who is the most alpha dog comes out on top and if you get skipped, you skip that bastard right back and prove to him you're a better/smarter person than he is with your actions, and not passive agressive bullshit.
I remember that thread a while back where people were making fun of Korea for having a massive male makeup industry. Its simply because of the competition for jobs. You're competing with thounands of smilarly skilled workers for the same hyperskilled jobs. You can't come out on top because of grades or experience, so many other people have the exact same resume, so you then got to go with personal appearence, give off a powerful clean look. USA has never really experienced that sort of competition so have no real bearing as to where to put their expectations.
When people from asian countries come to America, they don't come just because higher education is prestigious. They come because its SO MUCH EASIER to get anywhere because the USA is such a large place. Your placement in life is determined by a single entrance exam you study your ENTIRE life for, and its extremely stressful. You don't have any of that in the USA.
The government needs to stop its bullshit and get its act together.