People here are proposing intentionally creating image assets which collide with perceptual hashes of known CSAM (ignoring whether that is legal or ethical) and sharing those assets to effectively SWAT unaware targets.
Oh, I think I misunderstood you. I thought you meant instead of "sending images that collides with perceptual hashes of known CASM", why not "send actual CSAM in 'Facebook Messenger or Gmail or Dropbox', and since those services also use some other detection algorithm, it will also incriminate the receiver."
Those services will take your account through the same, if not more invasive, process if you are found with a hash match like the ones being proposed in these comments. Unlike Apple, they’ve built interfaces that surface all your account activity to reviewers.
In some ways, you can start to see the value in Apple’s system which lets the device user inspect what is stored in the associated data for later review.
I haven't seen anyone proposing actually doing it, but I think a lot of people are rightly pointing out that bad actors, black hats and the Russian mob are going to have a field day with their ability to do so.
I’m not sure how you can conclude the speculation is “right” without engaging with the fact that this hypothetical is addressed directly in the threat model document and hasn’t been pulled off successfully against any of the other services which do similar scanning. Why can’t I buy compromat as a service for your Gmail account?