I have not read all the posts on this subject but this is my 2 cents worth. Most pilots love to fly and all pilots love money so it stands to reason that more flying and money will be a motivating factor. I don't blame the Airline guys at all. There may be a moral aspect but we all live in the real world!!
The problem is the operators of the aircraft who use the airline pilots , they get free sim training and currency checks, experience etc (courtesy of SAA/Comair et al) They are the guys inhibiting the recruitment of full time or professional freelancers.