You criticize that the STF was not the organization that should have opened the inquiry, saying that using article 43 of internal regiment of STF was wrong. You replicate the arguments in far right groups. According with your interpretation, build a missile to attack the tribunal is not a "crime in the dependencies of the tribunal". You are free to have this interpretation, but this is not the vigent interpretation. Moreover, what you also are conveniently ignoring is that organizations that otherwise should have opened the case if the attack were not considered in the dependencies of tribunal, nonetheless agreed with the inquiry: https://g1.globo.com/politica/noticia/2020/06/10/agu-e-pgr-d... [source in pt-BR]
Several of your arguments, taken from far right groups, are weak:
> First of all, there is no "fake news" crime in the Brazilian criminal code.
This is just a term used in media. Show me an instance of someone jailed by "fake news". It does not exist. People are charged by crimes of threatening other people, unbased defamation, trying to abolish the rule of law, all of them are crimes and should be punished.
> Third, you cannot have the same person performing the roles of victim, prosecutor and judge.
If I threaten to kill all judges in Brazil, and create a plan to do so, according with you, I cannot be judged because any judge would also be victim in my crime? The fact is that there are cases where the STF has power to act, and that ridiculous argument do not overwrite this. Moreover, nobody is being at the same time judge and prosecutor. Inquiries are not criminal processes, they are administrative procedures. The criminal process comes later. And the prosecutor is not the STF, but the Prosecutor General of the Republic. Unless you have proofs that judges instruct and help prosecutors, like was proven in the carwash operation. But if this operation were carried like the carwash, Bolsonaro would already have been jailed. But fortunately that the due process in being respected in his case.