Context, in short, can make children seem ruder. Also, distracting technological apparatuses like Game Boys and cell phones may make childhood rudeness more annoying and vocal, full of beeps and loud shouting as well as the usual childhood crying.
If some children are indeed 'more rude' in actuality, however, the fault may less be that the children are not taught manners, but that they are imitating their friends. Children's peer groups often influence their behavior more than adult admonitions, at least on a daily basis. And finally, children may be 'taught manners' by adults, but they may be the wrong...
A child who sees a parent watch television during dinner is likely to do the same, as is a child who talks loudly on a cell phone in the library. These children are learning modern manners, they are not defiant -- but these are the wrong manners. Children may not care about minding their manners less than they did a generation ago. In fact it is very likely that children have similar anarchic urges to act out as well as to please adults as children of the past. But a constellation of social influences cause children today to seem to be ruder than the children of the previous generation.
