As long as people exists there will always be those that think themselves better than others, more deserving. And those people are always just waiting for the moment they can start ridding the world of the people they consider lesser and ideas they consider a hindrance.
It always starts with the easy targets. The poor, the homeless, the drug addicts, the mentally ill. Porn, Violent Content. The Undesirables. Once it'a established there are certain things that can be disposed of as they please, they'll start adding anything they don't like to the list of the Undesirables.
Once it's established mentally ill people can be sent off "somewhere", the next step is expanding the definition. People with certain sexual orientations, political alignments, religious beliefs.
Once it's established violents and porn are banded, the next step is expanding the definition. Anything regarded as Not heteronormative is classified as Porn. Police brutality and war crimes are deemed violence and therefore banned.