so then you would rather have it on icloud servers and completely in the dark ? having no knowledge of what is being scanned or compared against, having no knowledge of what kinds of images are being scanned ?
also, calling this a backdoor is really an inaccurate example of what is happening
apple is placing a database on our phones in full view of the users and the authorities, it is completely unable to be modified or changed since the hash is provided for everyone to see, we know that apple has obtained the images from 2 different databses so we know it is authentic csam and not any other kinds of material
it is figuratively sitting in the glare of a large spotlight ... to call this a backdoor is really entirely inaccurate
Of course it should be on iCloud server, but I'm sorry your demonstrates you don't know how Apple software works or where Apple suggest its NeuralHash tools are what they suggest make it more private, not the fact its on YOUR hardware, that cannot be more private because your system has unique identifiers that can be accessed by anyone exempt from Systems Integrity Protection (for some reason predictive text keeps changing Integrity to Information). Apple as software originators bypass that protection allowing modification.
If its by virtue of NeuralHash that its considered less intrusive, its not because its on your hardware its as Apple suggest NeuralHash, which would operate the same on iCloud...EXCEPT your software is on your machine all the time, even if you don't use iCloud! There to be modified at any time of Apple's choosing.
On iCloud there isn't the overhead of 1,000,000,000+ software downloads, same amount of users downloading it, so increased server traffic, increased processing use, increased electricity, and increased time loss for users installing it...
If you are downloading pictures to iCloud then the only check via the NeuralHash tools would be on iCloud, where it should be, because then you have a choice and you don't have lost processing power, you don't pay for the electricity, or increased battery use that you would on your system IRRESPECTIVE of whether you intend to use iCloud.
Being on every user's hardware is in no way conveys a safer system, its the opposite. It is far more dangerous, so much so that none other than Apple employees have kicked off about it being on users hardware and the serious implications of that.
Multiple media outlets have pointed out that its far more dangerous installed on users equipment, and I wonder how long it will be before a class action for slowing down users equipment, rather like the iPhone class action. It might be minute, but when it may scan ALL your photos, irrespective of whether you intend to load to iCloud, it also has the potential for much more serious modifications. If you are not using iCloud why should you have software on your system possibly checking photos or anything whether its intended to go to the cloud or not, but again where Systems Integrity Protection makes it so easy for such tools to be modified to target virtually anything.
If Apple are singing the praises of NeuralHash, then it will work no differently on iCloud should they choose to put it there, where they should put it there, because if you believe I cloud too will access data that is outside the remit of what Apple are claiming, then think how much damage it could be installed on your system and the capability of being modified on an individual user basis.