WARNING: The following article contains spoilers from Wolverine #4 by Benjamin Percy, Viktor Bogdanovic, Matthew Wilson, and VC's Cory Petit, on sale now.
In the most recent issue of Wolverine, Logan admitted he didn't believe in Krakoa. It's not that he doesn't think the island is a good place for mutants, especially since the children finally have a safe place to laugh and play. However, the problem with Wolverine is that he doesn't believe it will last and feels that everything he loves comes to an end.
It also doesn't help that Wolverine is not working very hard on doing his part to keep the community thriving and robust. The new issue begins with The Quiet Council calling Wolverine in to stand before them and Charles Xavier telling the veteran X-Man that he needs to work more cooperatively with the council. Wolverine checks off everything that he has done to help, such as stopping the Marauders from getting hijacked and taking out the pollen lab, and Xavier admits that much is true.
However, the problem comes with Wolverine disrespecting the entire idea of Krakoa. Xavier points out that they need to work together collectively. He mentions that Logan mocks the government there, and when he embarrasses Magneto, it endangers what they have worked to build. Wolverine got the Master of Magnetism drunk, stole his helmet, and then used it as a "piss bucket." To be fair, Logan needed the helmet for one of his aforementioned missions, but that doesn't stop the feral mutant from reminding everyone that Magneto tore out his Adamantium. It Wolverine's mind, he and Magneto can now "call it square."
This comment is a nice callback to one of the most horrific moments in the war between Magneto and the X-Men. It is also clear that, with as many holes that Logan has in his memory, he still remembers one of the most painful and traumatizing moments of his life. And he still holds a grudge.
This happened in the '90s event Fatal Attractions, where Magneto attacked Earth with an electromagnetic pulse that knocked out electricity all over the planet and caused thousands of people to die, including people in hospitals hooked up to ventilators. Professor X set up a team to attack Magneto, which included Wolverine, Gambit, Rogue, Jean Grey, Bishop, and Quicksilver.
The eventual fight with Magneto happened in Fabian Nicieza and Andy Kubert's X-Men #25 in 1991, and it proved two things. First, Magneto was always holding back, and as he said the words "the play is finished," he ripped the adamantium off of Logan's skeleton and out of his body. While Wolverine had every right to be still angry about this moment, what happened next was more horrifying. Professor Charles Xavier was also always holding back, and here he broke his one rule in battle. He attacked the mind of Magneto and wiped it out, ending the threat and finishing off Magneto once and for all. Magneto collapsed, saying to his old friend, "Charles, I never thought you would..."
What resulted was the entire world paying the price for this moment as Xavier's actions caused some of Magneto to merge with him, eventually creating the monster Onslaught, who would one day destroy the entire Marvel Universe. As for Wolverine, he was without his adamantium for eight years, not regaining it until 1999 when Apocalypse rebounded it to Logan's skeleton, first shown via flashback in Erik Larsen and Leinil Francis Yu's Wolverine #145.