My problem with 'bok choy' or 'bok choi', however you spell it, is that it's almost meaningless in Chinese. My problem; not yours.
Bok Choy is Cantonese, a language spoken by 4.5% of Chinese people. The majority language is what you probably know as Mandarin Chinese, another unknown term in China.
In Mandarin, it is 白菜 (bái cài) which literally means 'white vegetable', but more pragmatically just means 'brassica'. It covers literally scores of vegetables.
So when you tell me something is bok choy, I have no idea what you are talking about. But one thing I do know. What most Americans and British etc call 'baby bok choy' is never called that in China!
As I already said, and before the wicked witch berates me again, I repeat - call it what you will, but please try to understand my confusion.