This is the problem with idol/e-girl/vtuber culture. They think this person belongs to everyone and isn't allowed to have a life outside of that.
Yes, it's the problem, but it's also an original part of that particular industry. The idols get income from that industry, but in exchange for that they need to accept that consequence. If one is not willing to accept that particular consequence, they can choose to develop a skill that allows them to attract an audience regardless of having (romantic) life outside of the net. Obviously the regular virtual idol agencies aren't likely interested in that, it's not their business model, so it's up to the individual. But there's no end of people making videos on Youtube that attract even millions of views but still have normal relationships. They just have something else than just a pretty face and voice going for them. Like the skills/charisma to make interesting game playthrough videos or fix a broken car.
There's simply no fixing that problem since it's a part of the industry, a part of the way it makes money. Just like you can make money with a coal plant by selling electricity and heat, but it also produces pollution. There's no financially viable way totally around it, though you can try to deal with it to some degree with modern emission reducing technologies. The idols can use various means to keep their private life private. Reducing coal plant emissions isn't simple, hiding your private life as an idol may also not be simple. But either you accept it or quit.
