I think it's reasonable to argue that we have a bunch of local monopolies today, only that "local" on the internet is interest-based-local, not geographically local.
You mentioned Google Search, I'd add Youtube for video content, Twitch for streaming, FB for social network etc. Sure, you can broadcast video content without Youtube, there's vimeo or you could host it yourself, but it's really not a feasible approach. Much like you don't really have to rely on the local utility company to provide you with electricity and water, you could totally run a generator in your back yard and have trucks bring in fresh and move out waste water ... but it's not a realistic approach.
> To this end, I say "nope, you're not entitled... we have an open internet, drive your own damn traffic".
I'd respond that we don't have an open internet, but more importantly: you don't have to be a platform, nobody is stopping Reddit from being a publisher.
The reason why they don't want to legally be a publisher is simply that their low-cost approach doesn't work if they have more responsibility for what they publish. They very much want to be able to pick and choose what is published, but they don't want to be considered a publisher.