Money is only useful at a macro scale if it's in motion. These cash reserves are worthless if they just accumulate. Better to take them back into the US, and be distributed as dividends to shareholders or through buy backs than to leave them.
If that money could be invested internationally it would, and so basically the mere fact that the money is sitting idle in the bahamas is a huge vote of no-confidence in the other economies of the world. Every once and a while you used to see the big companies buy stupid expensive office space in London and other European/asian cities that were experiencing real estate growth. We see that less now probably because they are already well allocated in that asset class.
Now you may be thinking, well if it's better to take the money home then leave it sitting there for a decade, consider the following. If you repatriate the money and pay anywhere near the 35% corporate tax rate to do so you have to invest it in the US for at least 5 years with a 10% rate of return before you get back to what you had held internationally. Outside the fact that this is basically impossible to do with hundreds of billions of dollars... Absolutely no quarterly venture (wall street) is going to be allowed to do that, they will be sued into oblivion by their shareholders just for trying. Especially since the US regularly holds repatriation holidays. The only tenable long-term solution to this problem is to not tax corporate earnings from overseas. Tax them through individuals later, but not the corps. Otherwise Apple could exist in one form or another for 100 years with 100s billions of dollars just sitting overseas. Of course people who don't understand economics will argue that this is defrauding the US gov't of legitimate tax revenue, but my argument is the US is not the jurisdiction in which this money was earned, so it should see none of it.