It is a matter of where you draw the line. Consider the sardonic wisdom of George Orwell in Animal Farm. "All animals are equal - but some are more equal than others."
The philosophical difference comes about when you ask the question, "How do we achieve the greatest good?" I am reminded of the old Chinese proverb that is central to some of this topic: "Give a man a fish and you feed him for a day; teach a man to fish and you feed him for a lifetime."
It is the basic premise of the conservative side of the USA political spectrum that the greater good is based in self-reliance, not being dependent on the charity of others (long-term). Therefore, the conservative side of the battle pushes the ideas that nobody is motivated if they don't go out and earn their money like everyone else - by good, honest work.
The liberal side of the issue (as nearly as I can see it) is that some people, no matter what they do, cannot be totally self-reliant and make a decent wage. Therefore, they should not be penalized for their lack of self-reliance.
Again, it is a balancing act. Without incentive, nobody strives to do better. This is EXACTLY why communism eventually fails. Without incentives, production drops off a cliff and everyone gets the same. It's called starvation. Socialism when carried to an extreme also fails. The best definition I've ever seen is that "socialism fails when they run out of someone else's money to spend." Witness Greece as a recent major example of same.
It will always be about where you draw the line. And neither side wants to budge because they KNOW that at the moment, ANY movement is a loss for them.