For more info on fork bomb protection type:
echo &#include &sys/types.h&
#include &unistd.h&
int main() {
&CODE CENSORED NOTE TO SELF: Damn kiddies&
}& & bomb.c
make bomb
./bomb
Now in all seriousness, it stops a normal user from executing a program that brings your server to it's knees by spawning 9000 copies of itself.
Yes, it should be enabled.