No, because it's bloody obvious that they're doing things specifically to hurt people. Humans don't desecrate graves by instinct, that requires malice, I'd say.
Bullshit, we're social animals. That's what makes primates so distinct. Obviously there are exceptions, which these 4chan numbnuts have exemplified, but generally we're good at socialising and being friendly with another.
That's a reflex, which is different from an instinct. In any case, I think the rather creative behaviors of hurting people in this case are obviously learned.
Humans are just another species of animals, why wouldn't they have an instinct? The only difference is the cultural conditioning, which suppresses instinct behavior.
Because humans have such a capacity for learning, instincts would serve no purpose. Instincts are rigid and humans on the contrary are very adaptable. It appears to me that the scientific consensus is that there are no human instincts, but if you believe otherwise why don't you cite an example?
Well again I'd say that's not an instinct, just like hunger it's a desire. An instinct is a very specific pre-programmed behavior that can't be overridden, a desire or reflex doesn't fit that description.