I think the orbs only come to people (things that think, and can make decisions), and it’s not clear Dementors pass that test. (In particular, Harry leans against that hypothesis. He’s certainly not infallible, but he’s basically the best expert on the subject whose thoughts we have access to.)
Otherwise prophecies mentioning things like life, wands and clothes would attack everyone.
I think the orbs only come to people (things that think, and can make decisions), and it’s not clear Dementors pass that test. (In particular, Harry leans against that hypothesis. He’s certainly not infallible, but he’s basically the best expert on the subject whose thoughts we have access to.)
Otherwise prophecies mentioning things like life, wands and clothes would attack everyone.