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.
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.
Or if you don't care you can just ignore this persons messages.
He’s sent a couple more emails like that since. I don’t even bother to read them once I see the format.