You're forgetting that even if the police recover piles and piles of child porn, the defendent can claim that he created it all via computer. Then the police would have to prove he didn't - which is vitually impossible according to computer forensic standards. You must not have read the decision you're criticizing, because Justice Thomas's opinion addresses this issue directly. He says that, under current technology, it is possible to tell computer-generated images from real ones, and that, if technology ever makes that impossible, it would be constitutional for Congress to put the burden on the defendant to prove that his image is virtual, not real.
And I'm telling you the technology we have right now, can make it impossible to tell the difference between actual children and digitally produced children. That was useless as an excuse. And for the Supreme Court to say "Congress will fix it, when it happens" is a weasley and cowardly response to a problem that is here now.
You read the opinion again. What I say is true.