How much ignorance can there be here?
As previously said, this is an investigation into collusion as a reaction to consumer complaints which are quite valid under the current circumstances. Either the DOJ is blowing smoke to appease the consumer complaints in which case this will fade away soon or they have some real evidence and likely will push the issue.
Increasing capacity leads to more pilot demand which bleeds the regiona...um, excuse me... B-scale pilot groups which drives up average labor costs for the airlines which depend on super cheap labor to fly half their flights. This would be good for pilots as a whole but bad for United, Delta and American.
I think that has got to have something to do with it since it's the one common denominator all the big three airlines face but which Southwest Airlines doesn't have a real problem with....yet.