I actually agree with the OP. If you are being an ass while giving advice, then maybe the "I play the way I want" response is necessary.

I was in a Arboretum with my FC. Tank healer and me on BLM. We got a pug SMN. Now we're all high end raiders with extremely good dps, but everything was dying so slow. So I started watching the SMN. He had good gear, but was basically throwing shadow flare down and then ruin spamming with an occasional deathflare. Not a single DoT or Bane. So I VERY politely asked him his reasoning for not using dots. He said cause the mobs die to fast and it's a waste and he'll use dots when we get to the boss. These pills were taking 3+ minutes and we pointed that out to him in a nice way. Got the "I play how I want response" so got kicked. Sorry bro