Lots of people live in LA who haven't been to China in decades speak Chinese as a first language. The relevant question is whether there were many people on that cruise directly visiting directly from Wuhan/Hubei. LA-catalina-ensenada-LA? Doubt it. Not exactly the type of cruise someone flies thousands of miles for.
True. Like I said, it ain't like I was going around asking people if they're from Wuhan, lol
That said, you'd be surprised what draws tourists from mainland China; Las Vegas and Reno (for example) both get plenty of Chinese tourists looking specifically to gamble, and I'd imagine the ship's onboard casino to have a similar appeal. Plus, there were plenty of other tourists from long distances, too, both from within the US (East Coast) and from Europe and Australia (from what I gathered from the people whom I did talk to). So evidently there were at least some non-Chinese tourists flying thousands of miles for it; seems reasonable that some mainland Chinese tourists might, too.