Us tiktok shop with Chinese suppliers ?

I've noticed something that seems unfair on US TikTok Shop. According to their policies, US sellers aren't allowed to use Chinese suppliers. However, when I browse their marketplace, I see many TikTok shops with thousands of reviews and sales that openly ship from China. These shops aren't trying to cheat the system, as the TikTok app clearly displays the shipping time and country of origin - China. What bothers me is that TikTok seems to be enforcing their policy selectively. Some sellers are allowed to use Chinese suppliers, while others are not. This creates an uneven playing field and unfair competition. I'm wondering if there's something I'm missing or if there's a way to work with Chinese suppliers that I'm not aware of. I'd love to get some insight into this issue. As it stands, it appears that TikTok's policy practices are giving some sellers an unfair advantage over others.