As always, it depends on how the child was raised. I've met truly awful children - the scream just because they can, they treat the outside world as their own personal play-pen, and they show absolutely no fear of their parents. Good news is that these kids are usually around 7 to 9 years old. Afterwards, they tend to get a little bit better, to be honest.
I will say that young children these days behave worse than they did in my age. When I was in school, if the teacher told the class to be quiet, they'd usually be quiet. Nowadays, according to some teacher friends I have, kids at public schools act like chimpanzees. They don't want to learn, they don't want to listen... and it comes across in their academic work.
But classroom behaviour isn't the only measure of a person. The stats don't lie - crime, in developed nations, has been decreasing (that might not be attributable to the kids - I think crime has decreased because we have better forensic and information-processing tools necessary to catch them).
Kids are definitely more boisterous these days. Far less polite as well. But are they actually any more evil than the kids that came before? No. Not really. They're just louder. Are they more ignorant? Not really - most kids have always been ignorant, throughout history (most adults are ignorant as well for that matter).
They're more rude, I'll give you that. But I don't think they are morally any worse than the kids back in the 60's or the 50's. You see, back then the media and the news tended to, well, outright ignore children. They treated them as if they didn't exist. Nowadays, the youth, flush with cash from their parents, have become a major consumer force, and so the media pay attention to them and report their exploits and doings. This has led to a rather unfair amount of scrutiny.
Even if kids behave worse these days, it's also fair to say that adults behave just as badly. I've seen 35 year old men walk into a store swearing up a storm, in the presence of children. I've seen 50 year old men express extreme hostility and cruelty towards people just because they worshipped a different God than they did.
Adults are often quieter and less openly rude than kids, but in all honesty they're just as cruel, petty and nasty.