Well the video is pretty self-explanatory. It is not calling for equal distribution of wealth. It is calling for greater fairness. Why should poor workers pay a tax rate of 35% on their labour for example, while rich people only pay 15% on their capital gains? What kind of incentive is that to hard work?
We are not even talking about taking money away from the wealthy. We are talking about rebalancing a system that is heavily skewed in favour of those who already have wealth and against those who are working hard.