I see what you're saying.
I think playoff ball and season ball are just different. Yes, Green excels in playoff basketball, but I think Bogey does too. He's shown that in the past. Everything slows down. I don't think Bogey is as bad of a defensive liability in the playoffs. And we'll need his "size" against guys like LeBron, AD, Kawhi, etc. While he might get torched in some of those matchups, he'll help us some there more than Green would be able to. And he'll make those guys work on the defensive end.
Also, Don showed in Game 7 that he can defend at a very high level. However, he couldn't maintain the high level defense (shutting down Murray) along with high level offense (carrying us back in the 2nd half). Nobody can. If Bogey can alleviate some of the offensive burden from Mitchell, I think Mitchell can be more of an asset on the defensive end.
I'm okay trading Bogey for an upgrade. I just don't see Danny Green as that upgrade. Now if we're getting draft assets that turn into something else, then sure maybe.