That's why I don't think there is much of a point in trying to prevent people (e.g. by law) from crawling and using data in this fashion.
I feel like the only reasonable solution here would be to force these companies to rebuild their databases by legally limiting the lifetime of such data.
That way people have a chance to remove themselves from the database by changing/deleting their online profiles without having to use legal measures like GDPR requests. People wouldn't even have to be aware of any individual database they might be part of; they would be removed from it automatically at some point.
Another benefit of this would be that the pure cost of constantly re-crawling a giant dataset could act as a limiting factor and therefore prevent abuse.