I generally agree with a lot of your points, but haven't seen much of this negativity or hate raising to the top yet and only that would concern me and drive me away from steem.
I don't have any issues with the sheer existence of hateful or other wise immature posts. Do you?
I'm just curious what you are talking about, since you choose not to provide examples (there are good arguments for that) or point at least out where you see this kind of posts.
I my self only see real bad or destructive posts every now and then, when browsing "new" where you get all the posts before the voting takes place.