I feel like my eyes have suddenly been open *cue flashbacks of every yaoi/BL every read* (⊙…⊙ )
Nope.
I don't feel it's standard. I can name a few dark haired uke: Mono-kun who's architect boss sexually bullies him; Keigo-kun who ends up with a fair haired "seme wife"; most of all the stories with foreign guys who all have fair hair and are the seme's; and no one can EVER forget yakuza member Gotouda Aki.
When in doubt, check your own reading list: Lucky Paradise, The Deputy Wants to do it, Not Boyfriends Yet, Heal! Heal! Heal!, 24 Jikan Ochi nai Kiss, Fate Makes No Mistakes, Black or White, Punch Drunk Love, Ero Wizard's research Journal, Dear Sister I've Become a Blessed Maiden, Honey Bear, Nian Monsters in Love (Rabbit side), Head Over Heels for the Wizard! (both couples!), You Who Wants to Love . . . . do I need to list my entire collection?
What you say is not proof, that is an assumption you have come up with on your own. At this point, going through my 3000 + stories would never convince you, nor would telling you that searching tags for "light hair ukes" verses "dark hair ukes" results are to my favor (1 story for light verses 6 pages for dark). Until you can produce evidence contrary to what I've already posted, my mind cannot be changed.
I am not trying to change your mind. Nor do I need to. But yes I can give you facts
As of 10/23/2023, there are # of manga in
Yaoi - 228 (pages) * 48 (per page) = 10,944
Shonen Ai - 76 * 48 = 3,648
Total = 14,592
Excluding Dj from this = 11630
I have gone through around 6500 to 7000 manga out of this and created a block list for my self. The count as of today is 5464. I don't like reading manga with light haired uke or light haired seme who were r@ped as child or seme turned uke or uke turned seme. So all these are included in the block list. The last 3 tropes irrespective of hair color are not that high. But even in that, cases with light haired characters are more.
I have yet to go through 4,630 (assuming I read 7000 here) more, and I am sure I will find a lot more which I can put in block list.
Note:
1. The newly works are much more balanced than the older works. Like older works had a 80-90% rate and newer works around 65-70%.
2. Light haired person is not just blond. That's the reason I don't use blond when I make these statements. A brown haired person when drawn in black and white has white hair. Also if the Seme has darker hair than the uke, I consider it as light haired uke as well, because technically he has lighter hair.
Based on your comment you look like someone who is fact based. So I would appreciate if you could answer this question as I am collecting data.
https://www.mangago.zone/home/mangatopic/14613341/
I never said what I presented was proof. I said it's a fact. There's a difference.
Also, going by tags is not accurate. If you have to remember the location of a pin in hay stack, you would tag the pin rather than the hay stack. So people might have tagged dark haired uke more because they wanted to read only those, like I do. Who knows.
Heck, I try to look for trigger warning tags to avoid reading certain things and I have very low success. I always end up picking BL where suddenly I see things I do not want to see because the warnings were missing. If tags could have given an accurate picture then I would have saved myself a hell lot of grief.
When in doubt, light-coloured hair is almost always uke. Lol