Ninja looting

Last week, Gevlon claimed that ninjaing can be beneficial as long as it's from M&S (morons and slackers for those of you unfamiliar with his site.)

While I can understand his argument, I disagree with ninjaing items on the whole. It's a underhanded way of getting something you want.

For example, I was healing a pug group through Heroic Pit of Saron the other day, when Ick's Rotting Thumb drops.
The tank says, "Finally!" and rolls need.
Since he's the tank, so I pass, figuring he should get the item, making our journey to Scourgelord Tyrannus even easier.
But, of course, a dps death knight decides he wants it for his off-set and rolls Need.
The RNG gods side with the dps and the tank apologizes and quits, leaving the rest of us around to wait.

While, ninjaing hasn't taken an item I needed, it has abruptly halted my progress through the dungeon and wasted my time. Of course having nothing better to do than chastise the DK for his error in judgement, I did. If the tank hadn't left, I probably could have gotten the DK to turn over the trinket. Luckily, I haven't had to do convince many players to "do the right thing" and hand over ill-gotten booty.

While I understand that Gevlon is entitled to his opinion, I think any M&S stumbling upon his site are going to use that post as an excuse to ninja anything just to better themselves.
That's unacceptable.