So am I!
However, I can't say I listen to or follow Billie Eilish - I only found out about her coming out from reading this, in fact - but even as someone who's just mildly aware of her, I will say I've never assumed her to be straight. My gaydar's probably better tuned than the average person's but even so, I feel like her being some flavour of queer was fairly obvious and I wouldn't be at all surprised if that's influenced / shaped the kind of audience she has.
Unfortunately, I suspect an artist who's less obviously queer would lose a larger following for coming out. But yes, Billie Eilish only losing 100K followers is really encouraging still!
Nowadays, you have to assume your personal data being used to train an AI model is the cost of signing up to any free website unless they explicitly tell you otherwise.