Why the hell would CBJ do that?

Theyre shopping Anderson and they need defense help

Gee i know that Josh Anderson is having a abysmal season just like AA, But why would Columbus trade a 25 year old forward for an aging 34 year old Dman? Doesn't make much sense from Columbus's perspective.

Not for a 34 year old Dman they don't, Doubt Coburn would waive his full NTC to go to Columbus anyways. They're a borderline playoff team at best right now.

CBJ does not need defensive help, CBJ has a surplus of D and will most likely use D as trading chips.

CBJ is tied for second in goals against, tied for second in goals against per game, and possibly a few more defensive categories.

CBJ needs a goal scoring Left Winger or 2C

CBJ would also consider picks, but that would be after the season.

I also doubt Coburn waives his NTC, for Columbus.

Couldn't have said it better. The last thing CBJ need is aging veteran D man for Anderson. Yes Andy is having an off year, but he was injured for majority of it, and CBJ will not sell low on him.
Also, if CBJ does trade him, it will be for scoring help or draft picks. CBJ has a glut of top 4 quality NHL defensemen right now...Jones, Werenski, Gavrikov, Savard, Murray (injured), Kukan (injured), Nutivaara, Harrington, Carlsson, Peeke. Heck, Clendening can't even get into the line-up and is worthy too based on short stints up and his performance in playoffs last year.

Defense is CBJ's deepest position.