Other countries don't have that right enshrined in their Constitution. America does, so of course they wouldn't be hit with terrorism charges, Race doesn't matter here. You can show up to the airport with a gun, and as long as you don't threaten anyone or try to get through the security checkpoint, you won't be arrested. If you are arrested, the arrest will be thrown out of the court. Americans have the explicit right to carry guns in a not-overtly-threatening manner in a great many places that might surprise you.
My oblique point was that "not-overtly-threatening manner" is very subject to racist interpretation. There have been a number of well publicised incidents of black Americans being shot dead due to being wrongly percieved as threats, such as http://www.msnbc.com/msnbc/cops-shoot-and-kill-man-holding-t...
