Because sometimes, it's doesn't really help those people actually.
And I have a perfect example for this.

One day, we were 4 people (me as a healer) who helped a "kill party".
It was on Sophia EX. The other healer spend 90% of the fight dead. I had to raise her all the time and heal alone.
She got her clear, but doesn't mean she knows the fight since she was failing every mecanics even with explanation.
And sometimes, people who got their clears think that because they have it, they are able to farm while they can't.

+depending on everyone's playtime and schedule, some people don't want to help others because they don't have the time to. If they managed to farm for themselves it's great for them...
Keep that in mind when we are talking about "please stop making people waste time". Wiping again and again when they are trying to get a rare mount... this is selfish to always defend the new players side without trying to understand why the others are reacting like that