William Wang --
You can't leave to others the question of what's right and wrong!
Well -- to paraphrase a former president of ours -- you can do it, but it's, well, not right.
You're comparing apples and oranges when you talk about copy/pasting "articles," wholesale, and copy/pasting "passages," for use in writing of your own. The second is certainly fair use; the first is, at least arguably (commonsensically, if not legally), theft.
I agree with you to this extent: It's not the biggest deal in all the world. BUT! Seeing as how, by definition, everyone here is online and can conveniently use links to get to the sites of the copyright owners, we should use links whenever we can (as opposed to copy/pasting whole articles) when the material we want others to look at is copyrighted.