The reason those shops are based in China is because it's much more difficult to bring a trademark infringement lawsuit in China. Sell that same merch from your own site based in the US, and the rock band's lawyers will come after you.
They don't care where it's made; they care that you are selling it. If you used Zazzle or Cafe Press to produce the same item, you'd be at very least shut down by those US-based online marketplaces, as they don't want to be sued for infringement. You may not even get to the point of selling the merch; those services have many safeguards to prevent infringing merch from even being displayed for sale, and you will have to agree to a contract to not infringe on trademarks or copyrights when you first open an account. And if the merch ever saw the light of day on those services, you could be sued, too, by the rock band's lawyers.