McCain is not broadly hated. His net positive/negatives both within the republican party, and with the overall public, is better than all but Rudy.
A core conservative group hates him. But that seems to be a group that also almost universally hates Rudy (I use hate as a shorthand). Would that core group pick Rudy over McCain? Hard to say. There are so few things McCain is hated for that Rudy doesn’t fully support.
I’m not selling McCain, but he’s actually a pretty popular figure for some reason. Gingrich, now there was a hated figure (and that was before he sold out our party to the environmentalists).
McCain is disliked by conservatives of all stripes for having flushed the first amendment down the toilet just when we need it most: at election time.