मानुष्यं च समासाद्य स्वर्गमोक्षप्रसाधनम्।
नाचरत्यात्मनः श्रेयः स मृतः शोचते चिरम्॥३०॥
The human body is the means for achieving of the heaven and moksa and even after achieving the same, he does not do good to himself. After death he keeps on thinking for a long time.
देवासुराणां सर्वेषां मानुष्यं चातिदुर्लभम्।
तत्सम्प्राप्य तथा कुर्यान्न गच्छेन्नरकं यथा॥३१॥
It is difficult for even the gods and the demons to achieve the human body. Therefore after achieving the human body, one should act in a way that he has not to face the agonies of the hell.
The above verses are from TheDestroyer's answer.
And we all along find several verses through Hinduism saying this- Human Birth is extremely rare and auspicious. We must not waste it and effect our Moksha practicing Yoga (Karma, Gyaana, Bhakti, Kriya, Raaja Yog: means of attaining Brahma).
Now, God knows this very well. Then how can it (from 'it' I mean genderless Brahma) make some people Lunatic, Autistic, Schizophrenic et cetera.
There is no method of their Moksha(the highest duty of their Human Birth), until unless God itself comes to give them moksha, or Some Real Guru comes and enlightens them.
Then, Why God produces them like that, where it is certain they are never going to achieve no goals?
If it be argued- 'God gave those human being punishment of previous Karma' , then also God could have given them inferior births such as- fishes, birds, animals, et cetera. Why does God give them Human Birth?
Why does God need to deliberately make them Human Beings, and then deliberately defy this law- 'Human Birth is rare and meant to attain moksha.' .
Why does God need to create this 'divine holy body'(meant for Moksha) just to see it 'wasting'(as a lunatic person can never use his Human form for Moksha)?