Ahh, I believe the opposite is true. I rarely feel qualified to condemn other people, though there are occasional exceptions, scoped to very specific circumstances. If you mean "capable" of passing judgment I'd agree with you, because everybody does that, if only unconsciously. But qualified? That's hard to believe.
Yes, qualified. You don't need to be free from sin to say that it is wrong to nuke a city. You don't need to nuke a city yourself to know how the experience feels like, before passing judgement on those who do nuke cities.