五十歩笑百歩

In Chinese, this phrase is literally translated to, "he at 50-paces ridicules him at 100-paces". A fair approximation in English is, "the pot calling the kettle black". Why do I bother mentioning this? Well, aside from enriching your Chinese vocab by a picometre, I think it aptly describes a variety of people.
I'm hesitant to call them hypocrites, because it implies that they don't do it at all, which isn't really the case here. Nay, what I'm talking about here are those who are only half-way and yet look down on those who aren't. Case in point are the many students I've had the misfortune of meeting in the course of my education. English, being a rather common language spoken around here, manages to garner a reasonable amount of attention. And as all people discover at one point or another, not everyone speaks quite the same way. Some people use fancier words, some people speak more directly, others are very taciturn, etc, etc.
I don't think there is a "wrong" way to speak (except grammatically), but even then, it's a bit of a lost cause, since conversation is all about compressing information instead of elocution. But there are some, more often of foreign birth (like myself), who wish to rise above their birth and find for themselves a seat in society, instead of just one that is expected of them. These people will wish and want to better and improve their English, to be more natural, more intelligent and loquacious.
And that's not wrong. I myself am one such a person who was dissatisfied with what I was simply given, and decided to better my language through the efforts of reading a very large number of books. I encourage those who would seek to improve themselves and better those parts of themselves which they *can* change [naturally]. (Plastic surgery is something else, and something I don't want to get into.)
BUT, I do have a problem with people who are only halfway there and not only think that they're already all the way there, and who look down on others who aren't even halfway there. In this specific case of English and communication, it would be those who have perhaps expanded their vocabulary, maybe as much as 50%, but who have no concept of literature, or what it means to be literary. They condescend those whom cannot even bother with the few precious necessary seconds to look up the definition of a word when yet they themselves are no literati.
Words are only the beginning, my friend. It is how they are used in conjuction with each other, that they start to matter. Do not use a larger word just because it is sesquipedalian. I personally use a word because it fits and sometimes does the job of many words. It's a bit of an irony, but the more words one knows, the less words one needs to write. Consider:
"She threw her homework out the window"
vs.
"She defenestrated her homework"
Two whole words were saved, out of an original six. But I would still use a small word if it fit just as well. Promulgate may be a "good" word, but the phrase still remains as "spread the Gospel". Nobody says "Promulgate the Gospel".
I'm sure some of you can see a recurring theme here in my thoughts. It basically boils down to fractals, if I may be so bold as to make that analogy. We have an opinion of something or someone, which we may call our relation. And they in turn may have a similar relation with another person. But how many of us consider whether we are in someone else's relation? Visually, it's a self-repeating pattern, like two mirrors which are face-to-face. We are but one small reflection, seeing many smaller reflections, but yet not considering whether we ourselves are a relfection in a larger mirror.
But it's all the same! I know I'm not perfect and that's precisely why I prefer not to confront people about their flaws because I know I have mine too. But, one thing that I cannot abide by is people who look down on people for having flaws or characteristics which they themselves have (even if it's just a smaller degree).
I think Emily Post says it best when she wrote, "when you see a woman in silks and sables and diamonds speak to a little errand girl or a footman or a scullery maid as though they were the dirt under her feet, you may be sure of one thing; she hasn’t come a very long way from the ground herself," in her book Etiquette, published 1922.
In summary, it's good to strive to better oneself, and self-improvement is certainly no vice. But those who would look upon others with contempt shouldn't be so sure that they aren't so contemptuous themselves.