Actual information for those interested.

https://www.nasa.gov/missions/aqua/nasa-study-finds-evidence...

I don't understand how china show nothing for the chart "% of cloud clouds from ships.

Probably no data. China will not make data publically available if it makes them look bad.

How would they stop data from being collected by NASA satellites?

Presumably for the same reason the Gulf of Mexico doesn't show up despite having six of the ten largest US ports. I'd guess they only tracked the open ocean, but whether that's a design decision or those types of clouds don't form over certain bodies of water I couldn't say.

Either way, much of the traffic in the Pacific comes from or ends at China, I don't think anyone is denying that.

So the change in regulation happened in 2020. How then does this hypothesis explain changes in ocean temperature before then? What is the relative magnitude of the correction vs CO2-only-based models?

It doesn't. This model isn't an alternative to CO2 based atmospheric warming models, it just explains a very recent trend in ocean temperature. This branched off a discussion about recent temperature trends. Everyone asking questions about general long term trends either aren't reading or are starting a different conversation.

GP explicitly referenced this phenomenon in an unqualified manner when addressing ocean warming. If they wanted to be understood the first time, they should have clarified the context.

If you check, the GP said "the recent unexplained warming". That's sufficient qualification to say that this is the explanation.

Of course the sudden recent spike is on top of an existing warming trend. And that trends is due to long-term trends from CO2.

"recent" is enough of a weasel word that context is still needed.