Throughout history, many famous artists have created "questionable" (By some people's standards) as well as mainstream artwork. It is not a new phenomenon. Famed Disney Comics artist Carl Barks (Best known for illustrating the Donald Duck comic books and comic strips), Popular children's book illustrator and author Dr. Seuss, Osamu Tezuka (Best known for creating Astro Boy and revered as the "Father of manga"), Marvel Comics' Steve Ditko (Best known for designing Spiderman's costume and web shooters), Cartoonist Mort Walker (Creator of the Beetle Bailey comic strip) and others created all kinds of "questionable" artwork which many people were not aware of (See the following articles ->
here and ->
here). However, what is considered "questionable" artwork depends upon each individual viewer's standards. For example, some people have protested museum exhibitions or outside, open displays of replicas of MichaelAngelo's statue of King David, deeming the artwork as being "questionable" because the sculpture shows King David's penis in full, public view (See in the following article where it says "In 1995, a replica of David ..." ->
here). In that incident, some people in Jerusalem thought the statue was "questionable" while those people of Florence, Italy who tried to gift it, saw it as a replica of one of the great works of Renaissance art. What is considered "questionable" by some while not by others is a debate that might never ultimately be resolved. IMHO (Shared likewise by others), the "questionable" Kuronegi artworks which some people might view as hard core Hentai (ie. - Lolicon) might actually be, in the very worse light, soft core Ecchi (See "Wiktionary" [Scroll down] ->
here) since the subject in such a given illustration is not engaged in any sexual act nor are there any dark figures shown hiding in background waiting to pounce on the subject. In the very best light, those innocent artworks depict what can be seen in the normal, everyday, natural life of the subject. It is "Art imitating life".