The giant banners say this: although these are technical docs you may need to do your job, the most important thing you must see above all is an announcement of how morally pure we (think we) are. Once isn't enough. On our blog isn't enough. It must be the biggest and most eyecatching thing on literally every single page of our documentation. This indicates a lack of respect for the time and attention of devs. The implementation is also incompetent - the banner text appears to have leaked into search result snippets, thus reducing the utility of their docs search engine.
When Steve Ballmer jumped around on stage yelling "developers! developers! developers!" he was ridiculed because the outburst of energy seemed absurd and out of place for a CEO. But many of us appreciated the sentiment - that if you're developing an operating system then developers matter and their time/attention matters. Ballmer knew that. Platforms aren't chicken/egg situations where it's unclear what comes first. Apps come first. Users come for the apps. Then more apps come to follow those early adopter users, but ultimately, there had to be some apps to kick things off.
When the first thing you see at the top of the Fuschia docs is something totally unrelated to programming / the reason you were at that site, and which is irrelevant to most of the world as well, this sends a powerful message that the Fuschia devs are:
a. Staggeringly US centric. Their mindset isn't international at all. This is offputting to those of us outside the US. Fuschia's front page claims it's "an inclusive, open source effort". Not only have they never even tested it with a non-English locale, but they ignored the critical locale bug for so long other people had to fork the project to even make the emulator start up for non-English users [1]. That's about as non-inclusive as you can get yet is also absolutely predictable. Did we really need the blog to tell us that? Not really, we could guess it quite easily. The sort of people who demand such banners always seem to be hypocrites. It's called virtue signalling for a reason - people who do it announce their principles but never seem to live by them.
b. Not really rewarded for making developers happy. It reinforces a general impression about modern Google, that the personal success of the employees and executives is tied to things like the size of a giant black banner as much as whether their kernel is secure or their API docs are actually accurate.
c. As such extremely likely to manipulate their platform to prioritize the happiness of activists over that of developers. It's a bold statement of ideological allegiance. Who in their right mind is going to write an app for Fuschia that's braver than a shopping cart when they see that? Nobody smart, because you can guess what will happen if Fuschia actually does get apps: half of them will end up banned for some inane, impossible to understand reason, probably related to mundane use of language that's inexplicably become unacceptable since yesterday in California. The financial risk of developing for this platform is huge.
BTW: the Google doodles are pretty political these days, but in the beginning they were mostly reflecting things like national holidays.