I mean, Gandalf talks so much shit to Wormtongue... but it is almost precisely similar to Sarumon's shit-talking of him at the finish of the novel, an action that lead to Wormtongue's smiting of him with a sword, delivered, it is made to seem, righteously -- one is almost meant to feel momentarily good for Worntongue, in that he refused to be further degraded. Does Gandalf abjure total rejection of Gollum, Wormtongue and Saruman because he, being a Tolkien representative, knows each one of them is going to endure a period of being totally alone, of being naked, vulnerable, hounded, hated, and friendless -- and thus a far worse fate than any of the Fellowship has to endure, for none of them is ever THAT alone -- and that this fate is somehow actually undeserved for their representing a "crime" that is in everyone... that is in HIM?
What is Gollum? -- the most inquisitive and curious of his kind, so the text explicitly states. What is Saruman? -- the most heedless of established authority; the most modern. What is Wormtongue? -- an ambitious intellect, who makes a grab at things that ought to be available to all, but whom some proclaim -- the stupid and stodgy, that is -- absolute ownership of. Tolkien was chastising part of himself, the part that wanted to grow outside of constraints... and almost too much: verged on being conspicuous, drawing too much attention as to why so much over-hate?... as if the "guilty" party had to be punished to absolve the punisher any suspicious co-ownership of the same motives/motivations.
There's a bit at the end of the destruction of Sarumon's tower by the Ents, where Treebeard begins to identify with Saruman, saying, "you know, if someone did the same to me -- destroyed all of my home -- I might try and hide out in a hole too," and Gandalf replies, "No, you are not the least bit like him, for you would never destroy --" and I thought, what's going on here is that Tolkien is performing a kind of pseudo-empathy, pseudo-identification, through Treebeard, so that he can convince himself that he tried that... he tried to get really inside their head, when the truth is he has to keep some firm distance from them else go down the hellish hole of merciless punishment -- handed out by Middle Earth, if not by Gandalf -- they exist in the narrative to be destroyed within.