AI generates inaccurate & low-quality text based on plagiarized, opaque, and often low-quality sources. And if no one bothered to proofread, it's almost certain that no one checked for accuracy, which takes more time & expertise. The problem isn't proofreading, it's writing scientific papers w/ AI.

If AI is being used correctly, it should be indistinguishible from normal writing, or possibly even better than normal writing, because most people suck at writing.