No, you can't say the richest 1% of Americans are greedy, you can say they have more money to invest and spend less than they make so they gather more wealth. And many of the thing they discussed in the link I don't agree with and I'm not in the top 1%. I don't agree with the support increasing the minimum wage, does that make me greedy?
No, it means I don't agree that politics of minimum wage, as I feel that minimum wage tends to be the maximum wage for certain jobs. It doesn't make me greedy, it means I think the market should decide the wage. If you want to make more then upgrade your skill or become more valuable to your employer or start your own business.
While some people rich or not are greedy, you can't say that x groups is greedy just because they have wealth.