Err... a lot of those countries seem pretty religious (China being an obvious exception). Isn't a more likely explanation for the restrictions is that they believe porn is a sin?

I seriously doubt there are many dictators worried that porn will lead to the people realizing that they are better off without a dictatorship.

Exactly how would this work? So people would watch porn and then...? I don't understand your reasoning.
Heh, no. Dictators think that they know better, what is useful for people and country, they cultivate their ideas, and does not tolerate other opinions. So, if porn isn't part of their system of values, they prohibit it.
Okay, that could very well be the reason.

However, this does not explain Eric Cs view that the dictators prevent people from watching porn to stop them from overthrowing him or her.

So, control over people's sexuality gives them control over people, so they speak.
How does control over porn (by banning it), prevent uprisings?