Columbus just has a different team identity. I never thought Laine was going to be a good fit, especially back when Tortorella was still coaching. He tried to turn Laine into a two-way player/power forward, which just isn't really his game. However I can't really even say that the GM was at fault for bringing Laine in, because he was also dealt a crappy hand with Dubois wanting out. Laine was probably the best available option at the time.
It's just one of those things, Columbus needs that space to increase their depth, especially at the center position, meanwhile Montreal has found Laine to be the right fit for them as they're playing around his strengths. Columbus rarely utilized Laine as their PP cannon, their top D man and Laine just never really synced up.