A good amount of people are too egotistic to even consider the "art" in hentai. Basic mentality is, "Who gets off of cartoons???"
I'm sure we all know of people with that mentality.
Ugh. Yeah, I've encountered more than my fair share of that.
There's also the inevitable idiot or troll who, anytime somebody raises a serious question or wants to discuss aesthetics, chime in with "Why are you discussing this? It's cartoon porn. Just shut up and fap." (usually with far less eloquence)
edit: Hmm, I suppose I should give a recommendation or two for something to watch.
Hatsu Inu - Strange Kind of Woman, episodes 1 and 2. Unique characters, Fujino's wordless expressions are
very hot, and there's even a bit of humor in it.
It started diverging from the manga after these two, and - more importantly - the animation quality seemed to drop significantly, so I can't recommend episode 3 and onward.
Words Worth. Porn with plot, and also Stallion. What's not to like?
Sora no Iro, Mizu no Iro. Based on an eroge with art by Taka Tony, this anime does a very good job of sticking to T2's character designs.
Alignment You! You!. For the silly-minded. The characters do actually have depth, though. This one's for the /d/eviants out there.
(For those interested, the story in this is pretty far abridged, compared to the original manga by Matsumoto Drill Laboratory. If you're interested in the manga, it's one of SaHa's Donor Projects.)