Philosopher TM Scanlon writes an impressive piece here. First he puts forth philosophy in an accessible, interesting way. Complicated ideas and arguments can indeed be expressed in plain language - I wish more academics believed this. More importantly, he puts forth 4 solid reasons why inequality is bad for society (and thus why involuntary distribution measures are more than stealing from the rich and giving to the poor):
1. Economic inequality can give wealthier people an unacceptable degree of control over the lives of others.
2. Economic inequality can undermine the fairness of political institutions.
3. Economic inequality undermines the fairness of the economic system itself.
4. Workers, as participants in a scheme of cooperation that produces national income, have a claim to a fair share of what they have helped to produce.
Clink on the link to see his argument in more depth (and in his own words). I think regardless of your political views (and I do confess I whole heartedly agree with Scanlon's left leaning politics) you can see how this type of rational, clear, well-written argument might lead to better, more productive policy discussions than most of the political rhetoric we see today. Philosophy isn't just for the ivory tower!
These are not just objections to inequality and its consequences: they are at the same time challenges to the legitimacy of the system itself. The holdings of the rich are not legitimate if they are acquired through competition from which others are excluded, and made possible by laws that are shaped by the rich for the benefit of the rich. In these ways, economic inequality can undermine the conditions of its own legitimacy