It's a global and local problem, the top 10% in France earn the same as the bottom 50%, the top 1% of people in the UK take a 5th of everything, thats back up to pre-WW1 levels after 5% during the 70's. You can't solve the whole problem globally without solving it locally, nobody is saying the 75% tax rate is going to make the world a fair place but addressing the wealth gap is an important step in the right direction.
I've avoided mentioning the obvious issue of the better state the French government is in financially the more they can give in foreign aid up until now, but that's because it's a drop in the ocean, not because it doesn't help.
Top 10% earning as much as the bottom 50% doesn't look that bad to me as long as the bottom 50% can live a decent life for that kind of money. To be fair we're never going to get anywhere here, I have nothing against most rich people and I don't think taking all their money away is fair, that's all.