Some players don't listen. Some players are just flat out bad. Some will always be bad no matter what you do, or how good your intentions are.
...and that will never be an excuse for treating somebody like a lesser human being. If any of you call others stupid, retarded, or something similar for not being up to your standards in a video game - I suggest you take a good hard look at yourself. You might not be a problem when it comes to getting through content, but you have no integrity and make the world a worse place.
That's the same shit people pull in high school. Grow up, people.