Firstly the wealth created by hard work doesn't go back to the people who did the work. The hardest workers in society are often the lowest paid, i.e. labourers.
It is true, but today's richest people also had to work hard or to be very inventive to become rich. Bill Gates is a very talented person who created a big company and Windows is the most used operating system in the world. So he deserves it. It's not easy to do what Bill Gates did. The same is true for most self-made billionaires. They all achieved extraordinary things, or they were extremely talented in some area.
This is completely different from someone who simply buys bitcoin, and 5 years later, voila, he is a millionaire.
Plus if bitcoin does continue as many are expecting (to tens of thousands of dollars per coin and up) that will be the biggest redistribution of wealth in the history of man kind, which given the current state of wealth disparity I say is a good thing.
I actually think that this wouldn't achieve any redistribution at all. It would just reinforce current distribution even more. Those who were rich would become even richer, and those who were poor would become even poorer.
Today, most of bitcoin owners are young, educated, anglo-saxon men. People who already come from rich backgrounds. Those who can afford to spend money on it, and who can afford to lose money. And also those brave enough (and maybe greedy enough) to risk and to jump in it early.
Women are grossly underrepresented, as are minorities, people whose first language is not English, people from less developed countries etc.
And if you look at current distribution of bitcoins, it's way more unequal than general distribution of wealth in the world. Gini index for bitcoin economy is extremely high.