>If Joe Sixpack and Mohammed can communicate with each other they won't sit idly by while the fear-mongers use the other to justify terrorism/enforced liberty importation
is easily disproven by the fact that this still happens all the time among people who speak the same language. Speaking a different language doesn't help communication obviously, but speaking the same language doesn't magically remove prejudice and hatred.
Saying that example disproves the grandparent is being pedantic.
What they were saying was that "if Joe Sixpack and Mohammed can communicate with each other, [more often] they won't sit idly by while the fear-mongers [...]"
The counter-example of single-language conflict ignores the larger forest of language being a key leveller of cultural differences (i.e. necessary but not sufficient), as well as gp's obviously statistical rather than absolute example.
It's pretty clear he or she wasn't saying that 'as long as two people speak the same language, there will never be conflict between them.'
>If Joe Sixpack and Mohammed can communicate with each other they won't sit idly by while the fear-mongers use the other to justify terrorism/enforced liberty importation
is easily disproven by the fact that this still happens all the time among people who speak the same language. Speaking a different language doesn't help communication obviously, but speaking the same language doesn't magically remove prejudice and hatred.