I don't mean to make this worse than it already is, but I have to second this. If this sort of thing isn't an attempt to delegitimize playing D&D in a manner contrary to your opinion of how things should be, then what is it?
An attempt to stop sweeping generalizations in conversation?
Those people that call any RPG D&D don't help in communication.
People that are so obtuse to be so vague are just causing the deterioration of communication skills globally.
Why be so lazy to just say or type "D&D", when in fact you know it is 4th edition D&D?
I don't think typing on a forum anywhere will cause that many problems from adding the extra few bytes.
The half second to identify what you are talking about rather than generalize in the first place, removes the need for someone to ask you what you mean by it for you to have to take even more time to answer the question than if you had said "4th edition" in the first place.
Too many IM and texting people are corrupting the language due to laziness is what it is.
If you don't have time to formulate a complete thought, then don't waste another person's time trying to guess what you are trying to say.
Don't generalize, when you know you can be a little more informative and specific.
"I play AD&D 2nd edition" =/= "I played 4th edition D&D"
The problem is even bigger when you HAVE a proper name for something and generalize it. We might as well remove all peoples names and just define everyone by pronouns as he and she.