
That is normal, you know. Although he knows Kouichi's feelings, but because they are bestfriends, to say 'Im sorry I can't date you' is a very difficult thing to do. Kouichi understands that, so eventhough he confessed, he knows Katsura won't choice him.
And it's normal for being defenseless in from't of someone 'higher' than yourself. At least in the end, Jayapura stated that he felt guilty to Sou and Kouichi for hunting him with the sudden hugs etc.

I think you both are right. Katsura was kind of dense and defenseless around others - look at Takatoh - but when his back was against the wall, he always chose Sou. And he always tried to be as clear as was possible for him to be. If the other party doesn't get the hint that is carved in stone, the problem lies with them.
I dont think it's fair that Katsura can go around being defenseless kissing and hugging other people in front Sou, hurting him and not say straight up. But if the roles were switched he would have cried or bitch about it thats so not fair. Also the fact that he couldnt choose between Sou and Kouchi that was pretty fucked up if I were Sou I would have broken up with him a long time ago.