I am not quite sure I understand the thrust of your point, so sorry if I misrepresent you - feel free to correct me!
Firstly, white supremacists are nothing new. But they're also not being irresponsible (evil, sure, misguided, sure, but not irresponsible). It would defeat the point of having freedom of speech if people with controversial opinions couldn't express them for fear of having the right taken away. IMO punishing hate speech is OK in narrow conditions, but having a hateful opinion doesn't endanger freedom of expression.
As for Americans genuinely getting irresponsible... well, Americans do lead the world in dying of stupid accidents. I am not sure this has ever been explained, except perhaps for a cultural disregard for reading instructions. It's also not anything new.
Could you give an example of some way in which Americans are getting more irresponsible but comparable nations are not?