Simply put, resistance to the creation of a space frontier originates with the insecurities of Western leaders. First, it is clear that everything changes with the emergence of a frontier. Established power structures are usually shaken, not reinforced. (If this is not clear, try reading Walter Prescott Webb's The Great Frontier, particularly the last chapter, and Divided We Stand: The Crisis of a Frontierless Democracy, by the same author.)
So, the next time you're planning a big fishing trip, make sure you know when the moon sets and rises for that day and plan around it. You will find your fishing experience a much more rewarding one for having that bit of knowledge. I promise!
In fact, it may be much more reasonable to suppose that the American government's real capabilities in space exceed anything we have heard about, or can easily believe.