So let's do a bit of analysis: You have to be making over $400,000 per year (or have multiple millions in the bank) to be in the top 1% in the US. Everything under that is, by definition, "the 99%". The median income in the US is about $50,000 which would be "the 50%".
Median income is not representative of what most people would consider 'average' income. Let me illustrate by example; Consider the following 15 numbers --
The average is (rounded up) 13. However, the odds of you making average are better are only 1 in 5. 4 out of 5 times, if you're given one of those random numbers, you're going to be getting a "lower than average" number. This is essentially the heart of the OWS movement, and people like you who argue about "median" income are woefully undereducated about the realities of the wealth inequity distribution problem in the United States.
The rest of your argument is essentially based on this incompetent analysis of the situation -- using the average as though it still has relevance. If income distribution followed a standard gaussian distribution, perhaps, maybe, you could make the argument you're making -- but it isn't. It looks like a bathtub curve -- many at the low-end, diminishing into the middle before falling to nearly nothing from the middle to near the end of the y axis before skyrocketing upwards. It's pretty much the inverse of a gaussian distribution.
And making a "global" versus "local" comparison is apples to oranges. People in America deserve the wealth they are working for -- our economy is still largely closed, despite globalization. That is to say, the majority of what is produced is consumed here, and that our economy imports much more than it exports. What that means is, per unit of labor, the majority of the fruits of said labor remain domestic. However, the fruits of those labors are not being distributed equitably, and this is the heart of the OWS movement's position, and it is one worthy of closer consideration. Our wealth inequity -- that is, the spread between our poor and our rich, is staggeringly high -- higher than almost any other country on the planet.
Saying "People in Africa have it worse than you do, so shut up" is intellectually disengenuous -- it is a strawman argument. You are substituting a complaint about laborers not receiving due compensation with a comparison to people worse off. Well, there will always be someone worse off. That doesn't make what is happening to those "better off" less wrong.