What we've seen happen in history is the massive consolidation of companies. Look at the media industry, for example. It is now impossible to create your own TV network, and it will probably soon be impossible to compete freely on the Internet because the same conglomerates that dominate the cable and phone industry are trying to do the same thing with the Internet. I have two words that can summarize the entire thing: network neutrality. Complete deregulation is a bad idea; what happens if you take all the rules out of a football game? Everyone will cheat.
How does this relate to the topic? We don't like people who get their money for two reasons, in my opinion. We don't like people who are anti-competitive, and who try to dominate markets (such as the Internet, cable, and television industries) and intentionally want to stifle innovation. That's not contributing to society, and we all know that once a monopoly is established, a company has no incentive to innovate.
The other reason I personally dislike people with great wealth is because they're not being fiducially responsible. If America is going to be more capitalistic, the people with the money should be driving innovation, not stifling it. They need to act responsibly with their money, and that includes being philanthropic and charitable. When they just hoard it all and it becomes a competition to see who can hold the biggest pot, I don't think you deserve to have it in the first place (think Elon Musk, and how much money he has invested into SpaceX and Tesla Motors). What we have now is a massive gap in income disparity, and that's pissing off the lower and middle class. It's actually driving the middle class out of existence, and I would say at that point the wealth isn't being distributed evenly enough.
That's my take on why we dislike wealthy people. At least some of them. As the article pointed out, I really do think some self-made rich individuals rightfully deserve it and are acting responsibly.