Why? Because They Can.

AP News | How do Mass Murderers Obtain Guns?

In the end, there is no difference between New York and Texas or any other state. What all American states have in common is that they allow anyone to act on that most primitive whim of desiring to kill. Over 10,000 years of civilization have inculcated a certain tolerance and civility in mankind, but the outrageously permissive gun laws of the past twenty years have enabled and empowered those few among us who cannot control their primitive instincts to act on them without hesitation. When it is this easy to kill someone, it is not a mystery why people keep killing. They do it because they can.

Congress vs. Parliaments

The cause of the difference between the pathetic infrastructure in the United States and the excellent infrastructure in Europe lies in the fact that the European parliaments are deliberative bodies, whereas the United States Congress is merely a body.