I never saw a copy of this shirt again in Thailand (which was strange because Bangkok has many, many t-shirt stalls filled with shirts that would be controversial in the west). I googled it and discovered that there were actually many variations on this shirt[0], but I never saw the same design as the one the man was wearing.
Weirdly, this mystery was sorta solved for me this year. A Rudy Giuliani parody account I follow on Instagram posted an image of this controversial handheld game: https://en.wikipedia.org/wiki/Laden_VS_USA
The image featured on the game is the exact same one I saw on the shirt. And yes, several people on YouTube have acquired and played copies of this game: https://www.youtube.com/watch?v=3XNJM_Kamyg&t=142s
[0] https://www.google.com/search?q=bin+laden+vs+bush+shirt&tbm=...