So what would you consider a big deal. Obviously a 12 year old dating a 35 year old man for money isn't so I am curious what you *would* consider a big deal.
Your comparison here is a bit flawed. Obviously a 12 year old dating a 35 year old WOULD be a big deal. However, that is NOT the situation in this case. In THIS case the rumour said that Aibon, who would have been about 17 at the time, was dating a 22 year old Yamada. The age difference in this case would have been 5 years. It would NOT have been the 13 year difference that one would see in the example you gave.
Now the real question is, is it strange for a teenager to be dating someone who's older than 20? Yeah, probably. However, it HAS been known to happen. It DOES happen from time to time. There have been cases where the difference in age was not that big (like the rumoured relationship between Aibon and this Yamada guy), and there have been times where the age difference was very big (like an 18 year old Scarlett Johanssen making out with Benecio del Toro, who was in his 30s-40s at the time, at a party a year or two ago).
One also has to remember that historically, a teenaged girl dating a man much older than her was at one time considered normal. During the European middle ages it was common for 13-14 year olds to be married and have kids with men who were 20-30 years old.
Now for a lot of people (myself included), the concept of a 17 year old dating a 22 year old is uncomfortable to say the least. Personally, it is not something that I would endorse nor promote. However, if a 17 year old happens to fall for a 22 year old (and vice versa) and the two of them date and what not, that's their choice, and their life. Whatever our opinions of it, we have to respect their decisions/choices.