Grammar checks normalize text too much

I regularly run the text of this blog through grammar and spell check¹, generally a couple of months after publication. It's a great help. It finds both simple mistakes and cases where I was genuinly unaware of the correct spelling, grammar, or punctuation. Sometimes, the grammar check is plain wrong. That's okay. It's not always easy for a computer to correctly analyze sentence structure. Overall, it's wonderful!

But sometimes, it feels like it's removing too much of my creative freedom. As an example, a grammar check suggests that there should be a comma after "of course".

Of course John's talking about the other guy!

Of course, John's talking about the other guy!

I pronounce these sentences differently, but if I were to follow the grammar check, I'd always choose the latter.

Surely, written language should aim to be as rich as spoken language?