With respect (because I share the feeling), that's an attitude that helps one sleep at night in a broken world, but it's inherently defeatist and decreases the likelihood of positive change. Because things can be changed. Over the work of several decades, the murder rate (along with the violent crime rate) has gone down. Why should we just assume that the same can't be said for bullying and abuse?
There's plenty of question of how much we're willing to spend to solve the problem, of course (to give a terrible ad absurdium example, it's trivial to stop Internet bullying by shutting off the internet). But when we just hand-wave and say "Can't be fixed," we aren't helping.
When people stop posting PII online their abuse rates will go down. That's my conjecture.
In fact, personal abuse online has risen online and I blame people being so open with their personally identifying information. I made a related post on this issue here [0]. The solution is not one that people want to subscribe to. They'd rather share their lives on FB and Twitter for the world to see. "The world" includes nasty people and bullies. If people don't want nasty people and bullies to have access to this information, people need to stop sharing it with the world.
It is much easier to harass someone in a credible manner when you have information about them. No information? Nothing to attack. But so many people want to shove their name, gender, sexuality, religion, age, beliefs, and who-knows-what-else in front of everyones' eyes to see. So people who dislike _____ now have something to attack. People who dislike ____ will always and forever exist. Always. Until we remove the right for individuals to hold their own beliefs or have freedom.
There's plenty of question of how much we're willing to spend to solve the problem, of course (to give a terrible ad absurdium example, it's trivial to stop Internet bullying by shutting off the internet). But when we just hand-wave and say "Can't be fixed," we aren't helping.