Someone post that on Derpi.
Ponybooru, Twibooru, Ponerpics, Bronyhub: allow neonazi propaganda, allows racism & sexism, mostly ignore artists rights and wishes
Derpibooru: team seems undecided (my personal opinion), deletes the worst content, but not all of it. Respects artists rights and mostly also artists’ wishes.
Furbooru, Manebooru: do not allow neonazi propaganda or racist/sexist content. Tender to artists wishes. Also do not allow content which is considered to be childporn in many countries.