That is not at all what a hive mind is. What you're talking about is simply called social bias. A hive mind is a collection of bodies working simultaneously toward the same goal, as if they are of one mind.
What you're saying is true though. This however actually goes to show more weight for upvotes. While there is some merit behind the fact that upvotes can inspire upvotes, it does typically happen as a result of someone genuinely having a positive outlook on the post. People do look for posts that have upvotes and will read the thread to see what is going on. So ultimately, upvotes are a usually good measure for at the very least readable content.
Now the flip to this is that some people will just post something to be funny, and get a laugh out of people, then they get an upvote, then more views, then more upvotes, ... and then maybe a Rioter will waste a moment of their time on it, and still maybe get a chuckle, .. meanwhile good content is being overlooked.
I continue to fall back to my stance that a downvote should not be allowed without a comment because then we will know when a downvote has any actual merit or if it is just a troll. I would rather someone not have the drive to put forth the effort to type even a short comment just to leave a troll downvote, or at least then if their comment is something like 'You're dumb,' or some other unsubstantial garbage I will know that their downvote has no real weight. However, if they have a legit reason to downvote, and feel it is worth their while to vote, maybe they will comment with enough information to actually give constructive feedback.