LoveUniHatexams
Eastern Scripture (Gita) says those people who repeatedly show beastly characteristics take births as beasts with their attendant problems and diseases:
Bhagavat Gita 16:18-20: "Having taken refuge in false ego, personal strength, arrogance,
desire and anger, these malicious people detest Me even within their own bodies
or within others.
I dispatch such enemies of mankind, lowest among mankind, into material
existence where they perpetually enter into inauspicious demonic wombs.
After entering into demonic wombs through repeated births
without achieving Me, the foolish eventually go to the vilest destination [literally lower beings]."
Thus no injustice happens--everything happens according to people's choice:
Gita 14:18: "Those who choose to abide in the quality of goodness are elevated, those who choose to abide in the
quality of passion dwell in the middle and those who choose to abide in the quality of
ignorance, the basest of all material qualities, are degraded.
In other words, there is sufficient reason behind everything which may be perceptible or imperceptible for others.