In prison everyone struggles to form alliances. People usually do this by bad-mouthing other inmates whom they do not want you to ally with, rather than by giving you any practical reason to ally with them instead. “So-and-so is not good, you should be away from him”, is what you will commonly hear.
“Not good? This is prison! We’re all criminals.”
So you learn to take every man according to my personal experience with him, regardless of his case, regardless of what you hear about him. This remains my policy now that I am free.
“Not good? This is the Dunya! We’re all sinners.”
I do not believe that anyone is righteous (if only that could be an unchanging state!), but I believe that everyone struggles.
Perhaps you knew them when they failed in their struggle, so you think they are bad, and perhaps I know them while they are winning in their struggle, so I think they are good. But we have to keep in mind that the struggle is ongoing for all of us, every moment.