If you look at it through a scope, Twitter and Mastodon are two different flavors. Yet more and more, I am seeing these anti-Mastodon tweets about CP. While it was true than there was a instance on Mastodon in the early days that had this issue, the de-centralization means one and all others instance can block another instance if they are posting illegal content.
However with all these right-wingers, and seeing how Musk is starting erode a bit... there is a ton of fear tactics of telling people to not jump to Mastodon because its evil. It's show how much they need Twitter, because they can't get the clout they want on Truth Social or any other of these platforms. The fear of losing your grifting livelihood is sending them in a panic.