I agree, that's good perspective. I think encourage positivity it likely better worded. (Never been a mod, just trying to contribute.)

That being said and done, we need to remember that this is not reddit, and our community rules do not supersede the instance owner's code of conduct. For communities who are in lemmy.world, for instance, it needs to be noted what they say regarding controversial, "inflammatory", topics, and even free speech. It's very broad and nothing unreasonable, but might be good to remind people that all community rules taken into account, they stick to the rules of this community's instance code of conduct as well. It's not majorly complex, but lemmy.world does allow for what I suggested, thus making my suggestion just as simple as giving a link to the instance's code of conduct.

https://mastodon.world/about

I hope this helps a bit.