People have always been crazy. It's just that with the internet and so many forms of media, you hear about it more often and to be honest it's often dramatized. Not always, but very often. Also, people have more resources and technology, plus getting their ideas from other people (eg. the internet) allows them to fulfill their crazy thoughts in all new ways.
My opinion is that it all comes down to your upbringing. Even people with negative psychological tendencies can apply them in a positive way with discipline and firm, respectful parenting. And people with totally normal brains can use them for evil when raised by weak or immature parents. My question is... why don't we teach parenting as a standard part of the curriculum? In my 17 years of formal education, I was never required to take a parenting class of any kind, yet it's the #1 most important thing for the generations that follow. So far it's been that kids with good parents will usually treat their kids the same way. Kids with bad or absent parents might flip 180 degrees and be overbearing on their kids. Kids with strict or abusive parents might be too kind to their kids and let them get away with things which leads to them having manipulative personalities.