We're not talking about
imposing a 2pm meeting... we're talking about two people who
agreed to a 2pm meeting. (Imposition is something else entirely.)
Also, one thing I'd observe is that there's a difference between social occasions and business. Even as an American, when my family says they're going to show up at 2pm, I don't sit there at 1:59 at the door tapping my foot. However, business is different; if you've mutually agreed on 2pm and you come in at 2:40 pm without having checked or communicated, there is a problem there in many cases. There may have been further scheduled events for 2:30 (odds are good you're meeting with someone who has lots of meetings, statistically), or whoknows what. The casual approach to time risks having three unrelated meetings that were scheduled to be separate trying to happen all at once.
Whether firm or casual time is abstractly "best" is a hard problem, but when it comes to business effectiveness I don't have a problem saying punctuality is a benefit to getting more stuff done. "What if I don't want more stuff done because even that is an American thing to say?" Well, surely we'd all rather then get our things done so we can hit the bar freely later? And it isn't an American truth that businesses really need to accomplish things to survive and thrive, it's the nature of the Universe we live in, where we must work for our sustenance, however distasteful you may find that.