This seems like a logical step, both as a political counter move to the US limiting Huawei and TikTok, and as an actual security measure. If the Chinese state can get intel from Huawei devices, surely the US can get intel from iphones. I'm surprised they didn't include Microsoft.
Well that and MS is like a national champion in China. MS is one of the few companies to follow Chinese law and thus, Bing is the only foreign search engine allowed. MS is what China is hoping every other foreign company will emulate. So yeah, no way China is going to go after MS.
*Edit. Heck, MS is expanding in China even amidst the tech war because they love China so much.