Scott's voice over the intercom is tinged with a trace of exasperation and amusement.
"I can hear everything over the surveillance monitors. I could go into the psychology of what he's saying, but it boils down to 'he's a sadistic asshole.' Don't worry, it's not anybody's job to like him."
Charles Xavier would have said something about potential for good. He'd have suggested that if Creed could be reformed, he'd be as formidable an ally as he is an enemy. Charles Xavier is a noble, high-minded idealist.
Scott Summers is not Charles Xavier. While he believes in the Professor, and in his dream, in his absence Scott has been forced to be pragmatic and follow his own lead. In some cases, like Magneto, the situation can be handled with cautious optimism. But in Creed's...
...No. Whatever kind of hell he's gone through, he's done just as bad to other people. And unlike Lehnsherr, Creed gets off on what he does...he's alpha-wolf mentality at its worst. We may need his information, but I'm damned if I'm going to trust him one inch more than I absolutely have to.