My friend and I laugh about this age thing a lot. It seems to be an asian thing, korea and china do it too. I've seen male characters as young as 24 get referred to as a 'geezer' or 'past their prime'. I'm amazed they dont take them to the barn once they turn 30, the way they carry on.
They have different values and perceptions on men and masculinity. It is more attractive to them for a man to be pretty, skinny, very young, obedient and to 'fit in'. In the west, we typically see attractive qualities in men to be willful, unkempt, older, muscular, strong and to stand out. As western men get older these traits emerge or can be enhanced whilst in asia they begin to lose that boyish appeal and are supposed to be set in their career and family by their 20s, losing worth and appeal regardless of whether they have achieved those goals. Asia is really fucked up about age, gender and sexuality that at times i cant believe places like Japan aren't a third world country.
I wish I could like your comment cause you were exactly on point
I agree with your post in many points but I think that this is not the case all the time. Or to phrase it better through yaoi we are seeing a portion of the truth. What I mean is that even in these stories the seme most of the time is tall, with broad backs and masculine. I also read an article somewhere that the let's say "K-pop attraction " (I mean the effeminate style) is something that started roughly after ww2 and contradicts Japan's older male dogma. A lot of mangakas are very young people without real lifetime experience so their work sometimes oozes of teenage thinking (I mean even in our countries 16year olds think that 30 is old if you ask them). But even it is their core values, apart from their sexism which I believe will gradually disappear, Japan, China and Korea (and other Asian countries) have a lot of history, advancement and a lot to offer. I mean Japan and Korea are symbols of technology. They have same distance from the "west" way of thinking but hey, they are the "east". If they can acknowledge the female equality and also not kill themselves of too much work I think they are very interesting and I would like to get to know them better (something which will never happen as I am not rich and traveling there costs dearly)
The uke is 20 at least, I think 22 actually. The seme said that 12 years ago when he lost his parents he was very young so he is probably 37 to 40 max. Also I noticed (is it a Japan thing?) that men over 25-30 are labeled "old men" (shocking)