You aren't understanding the specific issue he's talking about. The marauder can use all the mods on the item, so the only difference between the marauder and the dps jugg is that the jugg can use the shell while the marauder cannot. In this case giving the jugg priority essentially means that the jugg "needs" the empty shell. As empty orange shells are very easy to obtain, it would be ridiculous to roll need on them.
I understand perfectly what he is talking about. 3 of my 10 level 50s are Sentinel, Marauder and Juggernaut so I can relate to what he means.
If there is a juggernaut in the team and a heavy armor piece drops the juggernaut should have it over a marauder, all else is pure wrong and considered ninjalooting. I would gladly support a vote kick if the juggernaut lost a heavy armourpiece to a marauder and ofcourse place the ninja on my ignorelist.
I have seen many take loot they cant equip saying they need it for the mods but it is still wrong and I will never support it. I still stand by my opinion that need is for the specific class and nothing else. If the player want a item for mods they can either ask the team or greed and hope for the best.