I don't know... I mean there are certainly some of those spammy comments on hive but they tend to be self limiting because 1) they don't achieve the desired affect and 2) they are likely to lead to downvotes, especially when left on whale accounts. And Facebook has its own problems with spam though it takes a slightly different form.
Also, while whale accounts may attract more comments statistically, that's true on places like Facebook and Youtube as well. The more popular you are, the bigger the audience you have...the bigger your audience, the bigger your account is likely to get (though that doesn't necessarily translate into money on Facebook...it certainly does on youtube though).
Facebook's advantage isn't in being more "genuine"...it's just in having orders of magnitude more users. That isn't likely to change quickly.