Re: "In other contexts, we use spell-checkers...
Well, and this is one of the major problems with grammar/usage/mechanics/style "checkers": even when they analyze text correctly, they're applying an extremely coarse and dubious set of heuristics. They can help some writers in some circumstances, but returns diminish rapidly for authors who are well-trained or attentive to matters of usage and style, or for writing situations with conventions that don't match the assumptions of the team that built the checker.
Even style guides written by human experts are problematic. Richard Ohmann's classic "Use Definite, Specific, Concrete Language" punched a hole in the style-guide concept in 1979, and most people have yet to get the memo.