This article sounds like it was written by the UMWA 

It begins with adjectives like "low" wages and "poor" working conditions (against what standard?), and goes on from there.  I'm not saying that such those adjectives are wrong, simply that they are debatable (and have been debated for nearly a century).  It would be NPOV to say that the stikers were protesting their wages and working conditions, without the adjectives.  NPOV also requires a decent respect for the opinions of the owners who sincerely believed that unions were instigators of violence.

Also, unlike the prior comments in this discussion pertaining to certain unfortunate edits, I'm not saying that there weren't innocent and ill-willed parties in this event.  I'm simply suggesting that the history clearly coughs up both types of people on both sides of this conflict.  Contrary to that scholarship, this article's premise is clearly that there was a "good" and "evil" side.