What is worse... being negative and criticising people? or being a terrible player who wants to do 50k dps when doing 150k is the norm and waste everyone else's time?
LFR is for everyone, and if you are sitting there expecting other people to do the work for you, you should and you most probably will get criticised. If you don't like it, invest some time researching how to play your class so that you are an effective team member and not a leech.
Aim of the game is to do something together as a team, that is impossible if you are a bad player and are expecting to get carried regardless of how many hours you spend playing the game.