The people of the world are definitely able to express there political opinions and engage with their politicians more than they were during the year 2000, and certainly more than the OP's comparison of the Roman Republic.

That being said, I also agree with your point. Censorship is a huge problem. In my (recent) studies of authoritarian states, I've found that governments do not typically implement censorship before the people. An authoritarian government will encourage/fund/organize groups of civilians to promote & demand censorship before they come forward with legislation.

While I'm sympathetic to the free-market idea and believe a company like Facebook can operate however they want (within the law,) I do see their actions as problematic.

Corporatism plays a role here too however. All big tech companies are embedded with government in some way. For example, the Snowden NSA revelations.