The Islanders are just one example of a poorly run club which is dragging down total NHL revenues. We can also talk about many other poor decisions made by other clubs and the league in general which caused the overall pie to shrink. How much would the league have made if the Jets had been in Winnipeg all this time? Phoenix had been in Hamilton? All of these things seriously piss off the NHLPA, which sees thiese as poor decisions which it had nothing to do with, which bring down the size of the "pie" they get to share, yet owners got large chunks of cash as relocation and/or expansion fees which the NHLPA did not get a piece of.
Putting aside all the numbers and fancy talk, the bottom line issue is really very simple. Since the last lockout, two NHL groups have done very, very well for themselves - the players and clubs at the top of the heap as far as profits are concerned (Toronto, New York, Philly, etc). Some clubs have not done well and need help. There really is no big disagreement that the poor performing clubs need help. The big fight is over who should pay for that help, or at least most of it - the players or the rich clubs. That's it.