"просто так" here is "without effort / simply".
"каким попало" is idiom close to "random". bride on wedding throws flower at group of maidens in random manner = "в кого попадёт". "who was hit?" = "в кого попало?". "каким попало" is some kind of reverse - life is "throwing random objects at you".
So, "(green) you cannot simply be (red) random disabled".