Your grandparents are full of crap.
As they grumble about how rap music is destroying civilization, what they don't mention is that the blues they were listening to in the 30s and 40s could be every bit as violent, sexually explicit and sometimes just downright insane as the worst gansta rap has to offer. Compared to some of these vintage lyrics the members of N.W.A are levelheaded concerned citizens, and Eminem's a regular damned feminist.
7Skip James Cuts a Woman in Half ("22-20 Blues" - 1931)
"22-20 Blues" tells the tale of a woman who just won't get her act straight. See, Skip James sent for her, on several occasions, and yet she didn't show up! The brazen audacity! Of course, in the world of blues, there's only one way to deal with minor punctuality issues: brutal, brutal murder.
Big on punctuality.
A Few Choice Quotes
Sometimes she gets unruly;
An she act like she just don't wanna do;
But I get my 22-20;
I cut that woman half in two;
Your .38 Special;
Buddy, it's most too light;
But my 22-20;
Will make ev'rything, alright;
Shooting your woman with a mere .38 pistol? That's for pussies. Ironically James soon found himself humbled when Robert Johnson recorded a far more popular version of his song. The only real change Johnson made? He upped the caliber and named it the "32-20 Blues." It was all about the gun size with those boys.