Consider it from their perspective. If they leave a job as a union-protected coal miner, their options are garbage, trained or not. They'll be going from a situation where they can expect and get reasonable compensation which grows faster than cost of living increases, pensions, etc to being treated like a cost center to be manipulated and reduced, forced to hop jobs every 4 or 5 years to even remain at market rate for their skill level, etc. You really can't expect them to not be defensive of their position, especially considering the history of open flagrant abuse and violence they've faced in the past.