It's a number of things. First off in other countries it's been ingrained in their cultures since the days of the Anglo-saxons and the Greeks. They are also farmed very early and built specifically for competing in the Olympics. If you look at the United States, if we have a superior athlete they usually compete in one of the main sports like football, baseball, or basketball. Other countries love their weightlifters and put them on a pedestal instead of those other sports.
Also, when was the last time you stepped into a regular gym and saw bumper weights or platforms for Olympic style lifting?
Lastly, the drug testing. The United States athletes are checked for drugs year round. In other countries they stop when it's time to compete.