Complex sentence: A new issue is your denigrating her beginnings, as almost without exception, every entertainer extant had beginnings in non-notable productions, and in a properly balanced and comprehensive BLP, those beginnings are expected to be written of and sourced.
Split into simpler sentences: A new issue is your denigrating her beginnings, as almost without exception, every entertainer extant had beginnings in non-notable productions. But in a properly balanced and comprehensive BLP, those beginnings are expected to be written of and sourced.