Dude just wanted to get a reaction out of his cousin that he didn't see very often, nothing more. It's funny seeing complaints regarding invasive inclusion, but good lord. He's a kid, he blatantly says he's not interested in being a girl, and he is boyish in every way except for his glorious mane. Still, the yaoi vibes are getting a biiiiiit too strong. Gotta tone it down with some more wholesome.
Also, seconding Arin-san. Traps are entirely different since they lure you in and surprise you with a pop up pirate. Saying traps are trans just means you're saying trans people are deceitful. I take a neutral stance, but even I can see why kids love Cinnamon Toast Crunch here. Kei is just a boy with nice hair, and unlike nii-chan's weird dream, he isn't a trap. Don't diss the nice hair.