Every generation has wrung it's hands over the horrible exceses of it's youth culture. In the '20s and '30s it was raccoon coats, fast cars, a hip flask of illegal booze, and sex. In the '40s and '50s it was "rebel without a cause," motorcycles, pot, speed, and sex. In the '60s and '70s it was acid rock, more drugs, and more sex. In the '80s it was coke, disco, and "safe sex." In the '90s the whole Goth subculture started up, along with gunge rock (and of course sex.)
The only reason today's youth have gone so far 'out there' is because it takes a lot to shock or offend today's liberal ex-hippie parents.
You only mention from the 20's on. Hmmmm, the 20's is when liberal ideology really took off.....