Some of it. The rest of it is on his own hands for being so d@mn fool as to go to North Korea and then give them an excuse to grab him.
Americans should not go to North Korea on a lark. Americans should not go to Iran or Iraq or Syria on a lark.
If one must be in a fanatic and dangerous place, one should put forth as low of a profile as is possible.
I am not even sure he took the poster. The video Norks showed about it is so grainy and perhaps digitally altered that you can’t tell who is taking it.
https://www.youtube.com/watch?v=SzVGIAcLsf8