Your suggested title is both vaguer and probably more wrong too: the thread claimed that cloud literally reflected the sunlight, causing less heat to go to the sea surface, there is no "masking" involved.

The current title is precise, the tweet chain is about sea surface temperature and the cause-effect of sulfur emission on the temperature. While it is related to global warming, and there might be other causes to sea surface warming as well, that is not what was discussed.