I think it's fine, as long as it was fed publicly accessible content, without any payment or subscription then it's accessible to an LLM as it is to you and I and that's fair.
And for the people that screech about LLMs being different because they can mass produce derivative works; first of all, ALL works are derivative and if machine produced works are compelling enough to compete with human produced ones then clearly humans need to get better at it.
The automatic loom took over from weavers cause it was better, if it wasn't then people would still work as weavers.