Sure, but in practice this is what true free speech on reddit for a large sub looks like before moderation
* 3 knee jerk replies
* 10 pieces of spam asking you to buy their bit/altcoin or click on their affiliate links
* 5 people who are hurling vile insults at you for whatever reason
* 8 more people who are hurling vile insults at each other, and just happen to be in your comment chain for some reason
* 1 reasonable, well thought out response
* 2 people who are lost and looking for a different sub
* 1 person replying half a year later after everyone's gone
Something in that ratio
With no moderation at all, you're lost in a sea of spam, scams, and insults. And because of the extremely poor SNR, your reasonable replies dry up and just leave.
I agree not everyone has to go the r/askhistorians route of completely iron fist, but you can't actually run a communication forum with millions or tens of millions of subscribers without a lot of automated and manual moderation. True free speech ends up being no speech because everyone got scammed or insulted and just decides to leave to go somewhere smaller. (edit: trying to untangle my confusing sentence)
It might work for smaller communities. It does not scale.