What Newsom’s office posted is called a “backhanded compliment” aka an insult disguised as praise.

In this case, Dubya (George HW Bush) was generally perceived to be a dumb guy: Freezing in front of kindergartners when receiving news of 9/11, using malapropisms such as the double negative “misunderestimated”, the whole “Mission Accomplished” staged scene on a carrier that turned out to be very premature announcement, in 2003, of the end of the Iraq War, which actually ended with US troop withdrawal in 2011.

Newsom’s Office is saying that Trump is dumber than Dubya, which is quite an accomplishment. (see what I did there?)

The tweeter 679 Enthusiast/@marionumber4 may not be literate or English proficient to understand this, and may be a bot, non English-proficient troll, or just posting whatever for a couple of clicks of validation.