Let’s start with the earlier show, Moonlight Mask a.k.a. Gekko Kamen.
Moonlight Mask was the first Japanese TV Superhero, paving the way for all others to come. The series premiered in February of 1958 on was is now TBS (Tokyo Broadcasting System) and told the tale of the mysterious masked hero who rode a motorcycle into action and dealt his foes harsh justice from the point of a gun. The series was an immense hit and spawned movies (produced by Toei for their first involvement with tokusatsu heroes) and a comic series. However, children began to copy the stunts they saw on the program and it tragically resulted in a child jumping to his death while doing so. Out of fear of liability, the series was cancelled in 1959 after the final story arc for a total of 130 episodes.
As for Kamen Rider Amazon, that’s a story of excess and pushing the limits coming back to bite the creators.
The 1974 entry in the popular Kamen Rider franchise broke away from the bug motif to create a hero based on a lizard. He was less of a skilled martial artist than his predecessors and relied on brute strength and animal ferocity in his fight against the evil forced of Geddon. The creators pushed things perhaps a bit too far with the bloody fight scenes and dismemberment of his foes that were the hallmark of the early episodes of the show.
Understandably, parents groups were not really thrilled with the spurting blood, hacked off limbs and a hero who would bite his foes. Worried their children might start imitating these violent moves, getting hurt or hurting others, they pressured the stations airing the show and the studio to tone it down. Even though they did make and effort to remove most of the more graphic content it was too little, too late and the show became the only entry in the Kamen Rider franchise to be cut short with only 24 of a planned 50+ episodes.
That’s the reason the show’s spiritual successor, Kamen Rider Amazons now airs exclusively on the Amazon Prime streaming service and is aimed at a much, much older audience.
This was also not the last time parents groups would have an impact on an airing series. Just this year, concerns about the hip-thrusting dance used during the closing credits of Uchuu Sentai Kyuranger prompted a quick change to a less provocative motion and, from what I have read, a new ending theme coming soon.