Reddit owns reddit.com so they can do whatever they want with it. And indeed, over time, they've added ads and analytics and generally made it more commercial and less user-friendly. This is a subjective opinion as someone who's used reddit off and on for the past 10 years.
My site is owned by me. I expect to be the primary contributor to it after the initial hype dies down, and I would prefer to spend my time contributing to a site that I control.
Privacy policy is at https://100millionbooks.org/privacy/. You can judge it for yourself. I run my own mailing list server and analytics server. There are no trackers on the site. Since launch 3 years ago, there have never been any trackers or ads on any 100 Million Books apps or extensions (not even affiliate links). That's a pretty good track record, and you can bet Hystoria will benefit from all of it.