http://www.ohchr.org/EN/NewsEvents/Pages/DisplayNews.aspx?Ne...
Censorship in internet. Opening private letters. Political detentions and raids to political parties offices, searching for posters and ballots. Bringing 10000 policeman by boat to avoid a vote.
Sound quite authoritarian to me.
Threats to the press, threats to polititians. Closing websites, chasing teenagers who fork a repo in github, opening mail, spying communications.
Check Julian Assange tweets to know a bit more about it. You cannot accuse him of being a part in this conflict. https://twitter.com/JulianAssange/status/914029345018122240
I think there's still a stretch from "there are corrupt politicians and the monarchy and president have a lot of undue influence over the judiciary" to "Catalans don't have freedom of expressions or are oppressed".
Spain respects fundamental rights in Catalonia and anywhere else in the country; respecting them is the supreme law of the land. Anyone who violates those rights will have the courts after them the exact same way as the courts are acting against this referendum.