And we must not conflate "weapons" with "rights."  

I think what you might be getting at is freedom of speech : freedom to laugh at.  I agree that expression, which includes laughter, is a right and a weapon.  But why specifically laughter?  The ability to laugh, which is what Sven said, requires first the ability to find humour in things.  No, not all people can do this, or do it well.  It requires some skill.  Not a skill taught in school.  No more than defending yourself on the playground is "taught."  

Come, my friends, 'Tis not too late to seek a newer world.