Those who oppose tackling mass impoverishment typically do so on the basis that:
a) any attempt to do so will be counter-productive: the economic system is a finely balanced machine and any attempts to improve matters will only make them worse!
b) the wealthy deserve their wealth and it would be immoral to ask them to do more than they already do to help the rest of society.
Point a) should not be taken seriously. But since it is, the whole of Part 2 of the book 99% is devoted to dismantling some of the many myths used to try to justify this position.
Point b) is more interesting. And there is some truth to the notion that to seek to end mass impoverishment without the cooperation of the very wealthy is doomed to failure. Fortunately, there are increasing numbers of those very wealthy who also see the need to tackle mass impoverishment. Most recently, Ray Dalio has been vocal on the topic. A little before that, an open letter from 18 US billionaires made the same point. And others, like Warren Buffett, Bill Gates and George Soros have been saying it for years.
The 99% have plenty of allies among the 1%.