It looks like it coincides with the growing paranoia that's been brewing for some time in the Imperial aristocracy's ranks. I have been to systems in the Empire a few times. Some years ago, I went to Duval City in Achernar. Aside from the exquisite beauty of the central city and the palace area, it's pretty much a normal Imperial town. The Empire may be a totalitarian state, but do not mistake that with communism or anything like that.
Capitalism is very strong.
Go away a little from the palace area, and you'll find traders. In their millions. Although they can't own spaceships personally, interstellar trade is still very important - they use the spacelines to move goods and services. These people do not look opressed or harassed, they are too busy trying to make a stack of money really to worry about the Empire. Free speech isn't an issue because the Empire didn't use to care what people said at an individual level.