Well, "card-cheat" is a characterization, while "pro gambler" is not; it's a term stating a person's line of work. There is no moral judgement in describing someone as a pro gambler. I would think calling someone in Wikipedia a "crook" or a "cheat" should only be acceptable if that someone has been convicted in a court of law, e.g. "G. Gordon Liddy is a convicted felon". (But O. J. Simpson is not a murderer.) I'll look this up in WP.  -