If you believe in Mark Twain's famous line "travel is fatal to prejudice, bigotry and narrow-mindedness", and if these earbuds promote travel by lowering the discomfort of communication, then you can expect that the earbuds would help reduce things like racial conflict.
Local sectarian conflicts are definitely a problem in lots of places, but a bigger problem in the US right now is that lots of folks never meet anyone outside their own culture. I'm not sure making it easier to communicate will help (lots of people don't even have passports...), but maybe it will, and I don't see how it could hurt.
I don't think so. We treated American communists with pretty much the same contempt --not that we were not right in condemning the ideology, which as we know leads to massive deaths due to ideology -gulags, cultural revolutions, etc., to reach "purity" but still, it's evident speaking a common language does not prevent us from treating others ill.
We see it from new-Nazis as well as antifa --they actually hate people with mainstream views and, for the most part, we're the same culture, writ large.
