It should be obvious.

Angular (meaning new new Angular — though the same applies to the older, but continuing AngularJS) is not a real open source project in the sense that Vue is.

Angular is created and managed by a team of top Google engineers — the Angular Team — for whom this is their highly-paid, full-time employment. Angular was created because Google management believes it in the corporation’s best interests to do so, and thus is a commercial project. Angular is open source only to the (admittedly very important) extent that you can read all the source code, and that you can submit issues that the Team can choose to act on. There are also some important people who are not Google employees who are highly influential on Angular, but these are very few.

Very, very few people would have even the pretense of a reason to fork the code, or even to show their support for the project by posting a GitHub star. They show their approval by learning it and using it in the real world, which is all that Google wants. I am a perfect example of such a person. I have devoted untold hours to learning Angular — even to explaining it on Quora to some extent — and most importantly, I have committed to the platform for my own business project. It has never occurred to me to “star” the GitHub repo.

By contrast, Vue is the classic true open source project. It is not sponsored or effectively controlled/”owned” by a specific gigantic tech enterprise, and permanently associated with it (as both Angular and React are). All sorts of developers have a chance to contribute in a direct and meaningful way to the project. There are solid reasons for wishing to fork the Vue repo. Seen in this way, it makes perfect sense to show support and approval for the project by upvoting it with a GitHib star.