Because Google is the gatekeeper to what you see, and Google prioritises the boring and bland and CEO-friendly websites you see.
I can find the most interesting and entertaining subjects searching in Japanese that do not show up when the same search is replicated in English, where it instead gives me something only barely related to my search that was simply popular enough.
It's quite simple how Twitter is actually a bastion of free expression, so long it not be in English.
Japan may have some areas they are more flexible with, but they have just as many, if not more that they rigid about too.
People are different, trying to make them the same would be just as boring.
People have long noted that one can get away with writing many things that would have one banned or removed on Reddit or Twitter, so long as one not do it in English but in another language. The same thing applies to Youtube's anti-swearword system that really only demonitizes based on English swearwords, not in any other language.