As the product lead for Flutter, I can assure you that this isn't an accurate statement. The product is several years old now, and we only added ads support in the last three months, in response to customer requests (https://github.com/flutter/flutter/issues/12114).
Flutter is open source, welcomes non-Google contributors, and is led by a group of hackers who think that UI development shouldn't be as painful as it is. One might have thought this would be attractive to the kind of developers who hang out on HN :)
AMP was supposed to speed up the web for mobile users. I'm sure the engineers that worked on AMP believed they were doing that too.
What's absent is a commitment to empower end-users in the same way that the web does now. Your doc puts the developer front and center, but "developer" can be read two ways: the person writing code who wants good tools that make their job a delight, or The Business that wants tools to enable them to deliver products that the end user cannot open open the hood and tinker with. A consistent UI toolkit that lets you develop once and deliver to six platforms is great for the coder, and if in the process it just so happens that the frontend is reduced to indecipherable pixels that can't be modified, ads that can't be blocked, and tracking that can't be escaped, well, that's just perfect for The Business.
I don't doubt you or your team's sincere good intentions. I really don't. But after pulling stunts like AMP, Tag Manager, FLoC/Topics, etc. Google, the business, doesn't deserve a charitable interpretation. It's like Prisoners of Geography. Google is an advertising company, and always will be. Regardless of the ideology or stated goals of the day, everything they do is to sell ads. If Flutter allows Google to display more ads and collect more data, and Google is funding the development of Flutter, it stands to reason that Google is purposefully pushing Flutter because Flutter will allow them to sell more ads and subvert user privacy.
It’s worse than an argument because their comment is not an argument.
They themselves need to substantiate their claims first before demanding evidence from someone else.
There's also a great Flash-like vector-based animation designer called Rive, which is itself written in Flutter (and generates code for Flutter): https://rive.app
Flutter is open source.
I hate google as much as next person on HN, but at least have some evidence.