researchers found 112 instances of known CSAM across 325,000 posts on the platform
So you're willing to vacuum up the hashes of every image file uploaded on thousands of decentralized systems into a centralized systems (that is out of "our" control and coupled with direct access for law enforcement and corporations) to prevent the distribution of 0.034% of files that are CSAM and that could just as well be reported and deleted by admins and moderators? Remember how Snowden warned us about metadata?
If you think that's a wise tradeoff, I guess, go ahead. But then I'd have to question the entire goal of being decentralized in the first place. If it's all about "a billionare can't wreak havok upon my social network", then yeah, I guess decentralization helps a bit but even that remains to be seen.
But if you're actually willing to do that, you'd probably also be in favor of having government backdoors into chat encryption (and thus rendering the entire concept moot, because you can't have backdoors that cannot be discovered by other nefarious actors) and even more censorship-resistant systems like Tor because evil people use it to exchange CSAM anonymously as well?