For some definition. Russia's FSB might have a very different idea of what this is. Anti-Putin memes, for instance. Navalny support materials or brochures. You'll have to watch what you download, because your phone might upload it and incriminate you.
Or China's MSS. Winnie the Pooh, Tiananmen Square, Free HK, etc.
Or even the FBI. Financial or political leaks, Wikileaks, etc.
Once they know who you are and why they don't like you, they can incriminate you in other ways. This helps them find and flag you. They don't even need to monitor and decrypt traffic - they can just upload hashes of things they don't like and let Apple's dragnet do all the work.
Don't buy into "CSAM" scare. It's never the intent. The powers that be don't give a damn about children. It's about power.