It says Mysterio tricked Wolverine into killing all the other X-Men.
Putting aside that Logan would probably figure it out by smelling the X-Men as he was fighting them, we hit the big wall: Half the X-Men would wipe the floor with Logan. Much like the Superior Spider-Man flooring him a while back reminded everyone...Wolverine is NOT a powerhouse. He's just a clawed guy who can take a beating. He's popular, and very deadly in close combat. But I remember back before his uberpopularity, his main role was getting his butt kicked because he was the hothead who rushed in first.
Like in the 90s cartoon, when he tried to take on Iceman...iceman just froze him in a block of ice, and he was helpless. He's VERY prone to mind control and psychics, which the X-Men are full of, and a lot of them are energy projectors, who would just blast Wolverine across the lawn. And all the various other mutants who are just flat out IMMUNE to being cut to death (Rockslide, dust, etc, etc)
I didn't actually read the issue, but it didn't sound like he snuck around killing them one by one. And if it was a big battle royale, Logan only even stands a chance against a few of the X-Men, at best.