Bungie's "reasoning" is that they do not want weapons to function differently in different game modes. They want each weapon to work the same across all game modes, and they do not want anybody to choose one gun for a certain game one just because it is much more effective in that area than anything else. Bungie does not want the guns to be situational. They want your favorite weapon to be able to follow you no matter what you May do. Its a good sentiment to have imo, But they go about it wrong. Nerfing ARs overall created more problems than it solved. If they had just nerfed it in PvP, or had nerfed It to a lesser extent in PvE, the auto rifle would work about the same in each. Instead we now have a semi-decent weapon type for crucible and a worthless weapon type for PvE.