CSAM is difficult to keep off these big social media platforms (it's the reason Tumblr banned porn). In the past, for some reason, Twitter made reporting cp difficult. They also ignored people reporting their own CSAM. The lawsuits are still ongoing, I think Elon is going to have to deal with those, too.
I'm trying to remember, but there's also an NYT article about a woman who begged to have the video of her being raped taken off Twitter. They ignored her requests, and only took the video down when asked about it by Nicholas Kristof for his article. I think the video was up for something like 6 years.
I guess what I'm getting at, is that Twitter does not have a good track record of dealing with this issue. Blaming Elon Musk for it is weird, because he is making it a priority, or at least he says he is. I trust the anti CSAM activists when they say the hashtags were cleared, and I wonder why the media aren't covering it. I suspect they don't want to upset their audience by saying anything that reflects positively on Elon Musk.