reporting in not working for a user.??

so there is this one user named steelsheen91 and if you look at his post history every single one of his posts are so damn indecent. see below for some examples

http://www.imdb.com/name/nm4363801/board/nest/222532962?d=222532962#222532962
http://www.imdb.com/name/nm3683325/board/nest/221237699?d=221237699#221237699
http://www.imdb.com/name/nm0942583/board/nest/150491246?d=219537717#219537717
http://www.imdb.com/name/nm1451549/board/nest/216145952?d=216145952#216145952
http://www.imdb.com/name/nm0659544/board/nest/215882684?d=215882684#215882684
http://www.imdb.com/name/nm1712157/board/nest/215601500?d=215601500#215601500
http://www.imdb.com/name/nm2467853/board/nest/215579601?d=215579601#215579601
http://www.imdb.com/name/nm4306422/board/nest/215300448?d=215300448#215300448
http://www.imdb.com/name/nm1451415/board/nest/215218236?d=215218236#215218236

so i report some of his posts but they never got removed while other indecent posts i report got took care by mods in minutes. so does anyone know the reason for this.??