you own your content, other users own their content

I think this may be confusing for laymen. From a copyright standpoint you are off course correct, you are the author and therefore the “owner” of the words you just wrote on Reddit.

But from a practical point of view the copy you send Reddit once you press submit takes a life of its own, governed by a very broad-reaching license, which for all intents and purposes means you don’t control that copy anymore.