In many ways, any writer who edits their work (and I would hope that is all of us!) self-censors. We look at the way we originally wrote a piece, realise we can write it with stronger words and so on and cut out the deadwood. We deliberately make choices as to what remains. Also we have to work out what our reader really does need to know about our characters to get the most out of the story. I can't think of any fiction writer who, preparing biographies for their characters (whether detailed or a simpler outline), puts every single thing into their stories! They would become top-heavy with information for a start. As for word count restrictions forget it, you'd never meet them if every single thing you created went into your finished piece.
The important thing, I feel, is whether writing non-fiction or fiction, is to ask yourself if the information is relevant to the reader? If you left the information out, would the article or story still stand? If the answer to that is no, then the information goes in and stays in!