I personally don't like hard wrapping the body of a commit message because it then looks terrible every where - GitHub website, git client etc. and it becomes much harder to read
Most clients don't wrap in a way that helps readability, though. Look at Hacker News comments for example. At 1:1 zoom the text is spread out across the screen in super-wide lines that are hard to read. The classic recommended 72-char hard wrap guarantees a good reading experience on all but the narrowest of screens.
I often browser HN in a half width window for this exact reason. To be clear, I don't fault HN for this; I can trivially resize my window to whatever works best for me. Commit messages are different because people often interact with them via command line based tooling.
What about parts of the commit messsage that shouldn't be wrapped and having them wrapped hurts readability? If you rely on soft-wrapped, then there's no way to prevent that from happening.
