Because it and last word were the only viable guns in the crucible for a few months. It was an absolute meta run by just 2 guns. people are just sick of seeing it because for a few months it was the only thing you saw. it was also pretty damn powerful even compared to other OP weapons at the height of their powers. I think they're bringing it forward though because in its current state the poison works more like a utility in crucible, better for tracking targets than killing. Unless it gets buffed, it coming back isn't really a big deal. people have just developed an adverse reflex to this gun. almost a super mild version of PTSD in a sense.