It's all about context, you could be the best player in the world with this warning, if you join a farm party you are setting yourself up for heavy judgement, and most times farm parties will be parsing so if you just fall behind which affects total raid DPS than expect to be removed. Hell, as people have noted, player who have cleared at times are worse than those who have not...but that doesn't stop a parsing player from removing them. Apathy at that level of commitment is pretty non-existent.