Most people in this game don't have tact and interpersonal skills. They don't know how to communicate without being rude, abrasive, and confrontational. This isn't FFXI either; they can behave like this because your reputation doesn't matter much and duty finder / data center matchmaking will still let them find other players.

Maybe a player would be open to advice with how to improve playing his role or how to manage greased lightning / enochian during phase changes. But he'll never be receptive to any suggestion the way most people say it. I mean, that's if you're making suggestions at all and not just going the confrontational route right off the bat. Know why all those duty / party finder groups break up so quick? Because they'd rather fight each other than the boss.

So maybe a player would be willing to improve. But he's just not going to care about what you have to say with the way you guys have been saying it since 2.0's launch.