Either that, or call them / walk up to their desk and pick a point from the wall of text and ask them to explain what they mean by it. Then watch them turn red as they have no idea what the message they sent to you means.
Sure, some people have no self awareness. In that case you can change your approach, if you are a manager or otherwise invested in the company you can put pressure on them to increase the quality of their work and to own the things they submit. Bring up specific examples of poor quality work, errors in documents/messages, etc.
Or if you don't care you can just ignore this persons messages.
This feels like a BOFH response but I'm strangely not opposed to it; If you generate something, you should own it ... regardless of what tool you used to generate it.
I have had coworkers say "Oh I don't know, Claude added that" in response to questions like that without even a hint of shame or self-reflection.