What that does mean is that extreme or sustained harassment that makes people unhappy, fear for their lives, or feel like they can't participate isn't okay. Communities that exist solely for hate aren't cool. But disagreement and even voicing opinions that are very unfavorable can still exist. Saying mean things to people is okay, unless that's all you do all day following around a user or something. We all become better people when we can share our own perspectives and hear the perspectives of others, especially when they are different from our own. Otherwise you end up with an echo chamber.
We're also okay with Imzy not being a platform for everyone—nothing is! And if HN and Reddit work for you, great. We're not trying to replace them.
What we are trying trying to do is build something for people for whom those aren't working. And most of the things we're doing different don't actually have anything to do with harassment or positivity. We've focused on creating really diverse tools so that communities can exist and share however makes most sense for them and do the things that they need to do all in one place. We've built in a payments system. We've tried to make things a lot more user and mobile friendly, as the places you referenced can be intimidating and not intuitive to a lot of people. Those are the things I'm most excited about--all the things we're adding to community functionality, not what we're taking away.