Spring Valley vitamins are not made in China. They are manufactured by a company in New York. The reason a lot of their supplements say 'product of China' or something similar is because many of the herbs that are popular as supplements (Ginko biloba for example) are grown only (or primarily) in China. So a huge percentage of the ingredients for ALL supplement manufacturers come from China.

I can't vouch for the purity of their products, but as someone who is poor and struggling with several long term chronic health issues, I can afford their products whereas I cannot afford all of the fancy name brand stuff that often costs 5 or 10 times as much. But I take more than a dozen supplements daily and they do what they are supposed to do. If I stop taking any of them I can tell very quickly as my symptoms get worse. Are there better brands out there? Of course, but usually at a much higher price. Lower purity products can still provide some benefit for those who can't afford anything else.

tldr: Spring Valley supplements are manufactured in New York, not China. It is many of the plants that are grown in China.