

But you still need the user accounts. Which must be created and are verified by email. Then you have to generate tokens for them to call the api endpoint to add the star. I’m not saying it isn’t doable, but it would be non-negligible and GitHub is going to squash you back at some point creating all those accounts from one source.
If a provided service is good and made accessible reasonably, I’ll use it and happily pay. As soon as it is intentionally obtuse or consumer hostile, say no more; I take to the seas.
But in all cases, I prefer FOSS first. It is generally better, more secure, has more vibrant communities, and represents a dying breed of freedom that we all need.