China is a currency manipulator. By pegging their currency - the yuan - to the US dollar, they can artificially keep the value of their currency deflated. Many economists believe that if China stopped buying US bonds, the yuan would appreciate to its natural state. It's quite a technical process that involves intricate knowledge of international politics, finance and macroeconomics. You didn't think China loaned the US money just to be altruistic, did you?
The consequence of such manipulation is that China can export a lot more of its products. That fits its whole economic model quite nicely. They don't excel at innovating, but they are quite skilled at copying and manufacturing at a mass level and low cost. That is why Wal-Mart and Target mostly stock items made in China. Exports are extremely price-sensitive. Ironically, when the US passed Quantitative Easing which flooded the market with dollars, China cried foul.
As for why I personally do not like buying products made in China, personal experience has showed that despite great prices, their products are poorly made and fall apart rather easily. Many times I have purchased small electronic items like cooling pads and USB-compatible computer accessories. They all stopped working after a few weeks. I was in the market for a tablet recently, but I could not find one that was guaranteed made in the USA.
Michael Melvin - International Money & Finance, 7th Edition