yanqui9:
Well, I don't know if Urd's a loli but she almost went full on straight shota with that one boy named Shuhei in "Urd's Little Romance." True, she was in child form herself for most of the episode but she kissed Shuhei in her adult form, I believe, and told him that maybe they'd meet again when he grew a little older.
I've read that the national age of consent in Japan is 13; however many prefectures have individually changed this to at least 16 in their jurisdictions. Ataru and Lum live in Japan, so there's no real problem legally to their relationship.
Lum's obviously not a loli. She's supposed to be 16-17 and, as above posters have said, this is within the age of consent in many areas, especially when there is parental permission and support. And even then, Lum and Ataru's "marriage" has not yet been officiated and made legally binding by ceremony, and certainly not consummated! Its more of an official engagement with witnesses (Ataru would probably say some sort of arranged marriage he's being forced into... before he got lightning shocked...!)
Lum does say early on that promises of marriage are still taken very legally seriously among her people (as they used to be in most our cultures until not long ago. You could be literally taken to court and sued for a breach of promise of marriage not so long ago).
As for that above referenced article, I'm going to assume (dangerous, I know) that its probably an American living in someplace where the age of consent is 18. People here take that very seriously sometimes and get really puritanical about it. Some places, even two "underage" teenagers like 17 or something can get in a lot of trouble knoodeling.
I think sometimes that people like this forget that while older people enjoy anime, UY and other shows were aimed toward younger people. Young teens and kids don't want to watch 30-40 somethings running around and being romantic (be like watching their own parents kissing...ewwww! lol ) They want to see people near to their own age or "older", like an older teenager or early 20s. So of course there's going to be lots of young characters in anime and manga and some of these are going to be portrayed as sexy, flirty, interested in sexy stuff, you know... like normal everyday humans.
Urusei0Yatsura:
Well in the words of someone from my anime society when we were watching Gurren Lagann, "There's some fanservice with Yoko who is a 14 year old girl, but in episode 12 she's 19 which means it's fine!"