Why some counties censor the internet.

Some countries censor the internet,like Burna,China,Cuba,Egypt,Iran,North Korea,Saudi Arabia,Syria,Tunisia,Turkmenistan,Uzbekistan and Vietinam.I think that this countries do this to prevent the population from acessing undesirable information.But i think that this "undesirable information" it's news writen by peoples that says bad things about the governaments,or their culture,but most the religion,of some coutries prohibit some things and the gorvernamet censor some sites that they consider "undesirable".The gorvernament of this countries are manipuling the information,because are not interessing for their another people giving thier opnion about the governament.The most os this coutries have a dictatorial governament that censor the internet and freedom of expression,and is not only the internet is censured but some of thiscountries prohibit tv prograns,movies etc.