Hypothetically speaking, here is what I HOPE has happened. Seibold has walked in, found a squad that wasn't overly happy with Bennett's departure to begin with, began implementing his own agenda as coach, immediately started copping pushback from the playing group in terms of attitude, then basically got them all together and said "Look, Wayne is gone, I'm in charge now and you will buy into that or ship off out of here.", which is exactly the attitude as coach he should be taking. HE is in charge, not the players. If they wanted to take issue with Bennett's sacking, they take it up with White, not Seibold, but clearly they weren't willing to do that because they knew White would tell them to grow up and get nicked.
The results of that are crystal clear: Kahu and McGuire are already gone (and question marks have always hung over Moose's attitude long before Seibold arrived), Nikorima is gone imo because he refused to be converted into a bench utility after being starting halfback for a whole season, and now Roberts is reportedly on the outer because he has always marched to the beat of his own drum, which Bennett allowed and Seibs clearly has not.
Individual fans will have their own opinions on this depending on which players they naturally gravitated towards that will depart/have departed, and that's fine, but you simply cannot deny that if things have played out like I wrote above, Seibold and the club have done the only thing they could have done. Judging by how everything has played out, I think Bennett had mentally checked out sometime around late 2017, probably due to internal machinations/club politics with White and the board (because if there's one thing Wayne Bennett is not foreign to, it's personality clashes born from power struggles), and as a result had allowed a culture of casual indifference to creep in to the squad, which has long been a suspicion of mine at least for quite awhile judging by their on field performances. The board noticed this and finally began taking action around mid 2018 when the media got a sniff of it. The rest is history.
If I am not far off the money, I am perfectly okay to stick by Seibold through hell and high water to get the players under his control. Personally, I will not tolerate a playing group that cares more about getting a free lunch than taking their role in the success of the team seriously. They are not there to put in a quality performance whenever they damn well feel like it, they're there to win premierships, and as far as I'm concerned, the aforementioned culture of indifference has long since outstayed its welcome.