The difference is that Reddit is a centralized community, where it's actually possible to moderate things without providing the tools for problematic censorship. Just like the comments on a private blog, where the owner has absolutely every right to delete comments or ban users.

On the other hand, if you give the same level of control to a decentralized network, especially to a pipe like Comcast that is often people's only option to access said network, you wind up with nowhere else to go when important things get censored.