Well, infortunately not just Chinese manhua, but there are many of these "dimwit" characters as you call it in mangas and Korean manhwas as well. It's just a BL thing. In this case it's the Seme that's just too mean.
Chinese have many character like this than Korea ヽ(`Д´)ﾉ
LOL, are we really reading the same thing? I think you're just very unfair and discriminating against Chinese manhuas.
To find pathetic and slutty Ukes in Korean webtoons/manhwas we just need to go on the front page of Mangago and we'll see many of these, even in the "popular": Killing Stalking, Dispar, Royal Servant, Stigma, An Easy Target, Love or Hate, Make me Bark, Obey Me, Painter of the Night... and many more. Even the titles says it all :D
Chinese webtoons especially BL on the other hand are for the very most Shonen Ai, so there are less of these "slutty" or very submitted characters as you describe.
And I'm sure that you know that 19 Days and Here you Are are Chinese webtoons.
I hate this MC typicall chinese manhwa MC character either woman or man always dimwit, fool, slut, masochistic character (〜￣△￣)〜