The issue is that you really can’t. The laws are written specifically to prevent plausible deniability. Because pedos would be able to go “lol a troll sent it to me” and create some doubt in a jury. Remember that (at least in America) the threshold for conviction is supposed to be “beyond a reasonable doubt.” So if laws were focused on intent, all the pedos would need to do is create reasonable doubt, by arguing that they never intended to view/own the CSAM.

This was particularly popular in the Napster/Limewire days, when trolls would upload CSAM under innocuous titles, so people looking for the newest episode of their favorite show would find CSAM instead. You could literally find CSAM titled things like “Friends S10E9” because trolls were going for the shock factor of an innocent person opening a video only for it to end up being hardcore CSAM. Lots of actual pedos tried using the “I downloaded it by accident” defense.

So instead, the laws are written to close that loophole. It doesn’t matter why you have the CSAM. All that matters is you have it. The feds/courts won’t give a fuck if it was due to you seeking it out or if it was due to a bad actor sending it to you.