So yes, this is wrong and he got screwed.
But...in his video, he actively says you can use this for full auto then toss it away. I think that's where he crosses the line. If this was sold as a novelty or art piece, I think he'd have been ok.
Basically he's an idiot who could've probably nod nod wink winked and gotten a slap on the wrist, but actively advertising illegal activity on YouTube was where he went too far. And being clearly not too bright, he thought he could run his mouth and advertise that the card WAS INTENDED TO BE USED ILLEGALLY AND THEN HIDDEN then fall back on the whole "it's just a picture, bro."
Do I think its bullshit? Yep. Do I also think he brought a lot of trouble on himself with his way of going about it? Also yep. We have to fight for our rights, but we have to be smart about it. He's like a kid in the principal's office who's all "I told the teacher to TRUCK off, you can't give me a detention for that!"