Why is the Tiger/German Suplex wrestling move so popular among anime culture?
Yes, it's very likely because of the popularity of puroresu (wrestling) in Japan. Antonio Inoki is credited with making wrestling popular in the country and he himself was impressed with and inspired by the amateur wrestling style of Karl Gotch (nicknamed Kami-sama) who had become famous in Japan. The German suplex was Gotch's signature finishing move.



There's a compilation of Gotch's moves on YouTube.