It's true that it's an outright offense to human eyes.

[He admits it so easily..! But he still makes no effort to take down the decorations, instead stepping away to regard anew the results after a job well(?) done.]

But there are more than human eyes around here, aren't there?

We shouldn't discriminate.

[Dazai is a terrible person, and he should feel terrible. But he doesn't.

Not that he's going to protest if Kim wants to take everything down. Dazai did his share, as far as he's concerned; he played nice so he could curry favor with the bosses. What happens afterwards is everyone else's problem.]