There are a lot of people there that haven't experienced oppression personally and genuinely believe that "strong ruler" that "keeps people in line" is what's needed for their country to be "strong".
Also one of the key points of Russian propaganda that has been hammered into them for decades is that "democracy is a sham" and that any alternative to Putin's regime would be just as oppressive and simply less "competent" (and therefore lead to Russia's ruin).
Putin supporters do not believe that democracy can work and they don't want democracy, as simple as that.
They don't even need to force it. Every ISP in Russia has government-managed DPI hardware that filters all use traffic performs such blocking. No cooperation from ISPs is necessary.