I have started to compile a list of instances of suppression of scientific ideas in history. Up to now I have collected the following points:
According to Dioganes Laertius Anaxagoras was imprisoned and then exiled because of impiety. He had claimed that Helios is not a God but a heap of glowing stones.
The cases of Giordano Bruno and Galileo Galilei are well known without sources.
Cavalieri and Torricelli (a pupil of Galilei), two protagonists of infinitesimals, were harassed and finally silenced by the leading Jesuit mathematicians. "Once the Revisors had issued their decision, a well-oiled machinery of enforcement sprang into action." (Amir Aleander: "Infinitesimal", Oneworld, 2015)
Brouwer was fired as an editor of Mathematische Annalen by Hilbert in 1928 because of incompatibility of Hilbert's and Brouwer's ideas. In this case Hilbert acted immorally and went beyond his legal rights. The whole story is given by Mueckenheim https://www.hs-augsburg.de/~mueckenh/KB/ from KB 548 to KB 658 under the title (coined by Einstein) "Krieg der Frösche und der Mäuse". The text is in German but with many English documents, some of them published for the first time.
Few years later the "Jewish science" was banned from Germany, among it the theory of relativity (100 Autoren gegen Einstein).
I am interested to collect more instances of suppression of scientific ideas. (I know that in Soviet union every author of a scientific book had to praise Lenin as the best human ever or at least had to quote some important phrase of his, but that is not what I would call a suppression.)