I agree, in the old days, players who did not abide by the social rules of a game did suffer the consequences. Ninja looters, trolls, cheaters were shunned by the community and (often) kicked from their guilds. Moreover, the stigma would stay with the offender for a long time because everyone remembered his name.
That all worked because:
a) the games were small and the communities were tight and
b) teams/guilds were essential to progress.
SWTOR has about 10000 players on each server. Loot and gear is easy to obtain in various ways. You can certainly level to 50 without ever having to group. And if you really put your mind to it, you can even have an end-game toon without teaming.
Being ignored by a few people is not a very effective deterrent, especially if you are a tank or healer. With 10K players per server, you will still find groups. The stigma of being a ninja looter, exploiter or troll might last a week at best. After that, nobody remembers your name, or what you might have done - one of the drawbacks of internet anonymity. Being kicked from a guild has even less of an effect. Guilds are not essential for progress and you could find a new within minutes if you choose to.
For all practical purposes, social consequences for bad behavior do not exist in SWTOR.
That is why I proposed a simpler, more automated loot system, especially with F2P arriving soon.
Everyone rolls "need" (or passes) and the random generator awards the loot.
Fair, equal and and without drama.
I'm pretty sure you didn't actually think this through. First: the drama will STILL be there if, say, a Sage does NOT pass on a Jedi Knight gear token when there's a JK in the group. I would be disappointed if it happened to me because as Kitru explained so eloquently, I do expect people to adhere to a social contract. If I do not expect that, any form of social activity (and online gaming is a social activity) becomes impossible, except PvPing in real life.
To not have any loot drama in groups, you would have to eliminate rolling and just have a random generator award the loot. Can you imagine the complaints that would cause? Well you don't have to: there's a reason why Bioware quickly abolished that system for story mode Operations. Nobody liked it.
I'd also say that your suggestion might hold some value (well, if we ignore the aforementioned flaw in its logic) IF the majority of players were actually selfish. However, they aren't, this is simply not true. I played on four different European servers by now and the vast majority of players I ever grouped with adhered to the unspoken loot rules. Yes, I encountered ninjas but they were a tiny minority compared to the players who rolled Need for their own class and spec, Greed or Pass for everything else.
I believe Bioware made a much better change that what you suggested, with items being tradeable within the group members for a limited amount of time. This way the actual "ignorants" can be made to see and rectify the error of their ways while the die-hard douchebags can be weeded out, kicked and ignored if necessary.