My beef with the thumbs-up feedback issue is not with the content of the feedback responses, not about what they mean, not about how convenient it is to click the thumb, not about how cool a cute little "thumbs up" button is. It's with the point score that Epic tabulates from these little thumb-clicks we make.
That point score is numerical. Its purpose is to compare one person to another, nothing else. The point score, if made visible (one day in the future), will follow that person everywhere. They will be judged by it. Not by the color of their skin, not by their gender or age, not by their religion or ethnicity, but their score. If/when this score is made public, then some people are going to be seen as having "more" of some kind of goodness than others. And we'll believe it, because it's a number, and because we made it. Numbers don't lie, right?
More or less goodness of what sort? More respected? Liked? Relevant? Entertaining? Insightful? Cool? More worth listening to? Comparisons will be made (that's the point, right?) and responses to each other will reflect the point score. People with low or lower point scores than others will suffer. If you are participating in this thread and you have a nice big point score, please consider the situation for those who don't. It's your responsibility to think of the whole community, not just the part of it that you belong to.
Think this through; putting a point score on people matters.