A companion is part of your character
anyways, if they make a fuss about a blue 22 mod, then they are silly, you can buy those for 2k on the GTN.
It has nothing to do with value or gear. It has to do with respect for the group. Everyone's time and effort is just as valuable as the rest of the group. No one is more entitled to something over someone else unless it is a upgrade for them. If it is for you and a upgrade then need, but if it is for your companion, then greed, unless the group gives you permission to need. They have just as much right to it as you. If you want the mod so much and you don't want to ask if you can need for companion, then go buy in on GTN for 2k.
I find this really funny since I normally hit pass on anything but mats and legacy stuff, but I still watch who needs and greeds.