It's a URL list of child abuse content?

That from time to time contains all kinds of false negatives and does a subpar job, see https://en.wikipedia.org/wiki/Internet_Watch_Foundation_and_... and https://fuwafuwa.moe/transparency/cocaine.ninja/2016-07-14.d... - which means that the ISPs do not "rightly so" block sites mentioned in said lists.

But even then if they did their job perfectly, not everyone agrees with this censorship policy. "ah yes, I will intercept your DNS queries and censor anything related to certain sites which I do not fit within my personal moral framework" is not something that I agree with.