Truth about dalits

Dalits are the favorite topic of anti hindu and anti national forces to defame India and it's largest practiced culture (hinduism)

What if I say it's entirely societal not from scriptures.

Check the following verses

jātau vyāsastu kaivartyāḥ śvapākyāstu parāśaraḥ | bahvo'nyepi vipratvā prāptā ye pūrvā advijāḥ ||

The sage Vyasa was born of a fisherwoman, and Sage Parasara was born of a Chandala, many were those who though not previously brahmins attained brahminical status. (M.B. Aranya-parva 312. 106.)

The Mahābhārata also says that it is the qualities of a person that matter - not their birth status.

satyam, dānam, kṣamā, śīlam anṛśāsyam tapo ghṛṇā | dṛśyante yatra nāgendra sa brāhmaṇa iti smṛtiḥ ||

O King of serpents, he in whom are manifest truthfulness, charity, forbearance, good conduct, absence of malice, austerity and compassion is a Brahmana according to the sacred tradition. (M.B. Aranya-parva 180. 20).

So it actually says the nature of brahmanatva is not by birth
One becomes brahmana by thorough study of vedas, and trikala sandhya  and his actions.

So it's the same for shudra Or vaishya it's their nature which assigns them to particular varnas

“O Arjuna, the activities of the brahmanas, kastriyas , vaisyas and sudras are clearly divided according to the qualities born of their own nature.” (Bhagavad Gita 18:41)

“The actions of a brahmana arising from his own nature are serenity, self-control, austerity, purity, tolerance, honest, knowledge of the Vedas, wisdom and firm faith.“ (Bhagavad Gita 18:42)

“The actions of a ksatriya born of his own nature are heroism, exuberance, determination, resourcefulness, without trace of cowardice in battle, generosity and leadership.“ (Bhagavad Gita 18:43)

“The actions of a vaisya born of his own nature are agriculture, cow protection and trade; also the actions of a sudra born of his own nature consists in service to brahmana, ksatriyas and vaisyas.“ (Bhagavad Gita 18:44)

“Following each his own activity, a man achieves finally perfection; now hear how the performer of action prescribed according to nature attains perfection.“ (Bhagavad Gita 18:45)

śūdrā vā bhagavad bhaktā niṣādā śvapacā tathā | dvija jāti samā manyu na yāti narakāṃ naraḥ ||

I consider a Sudra, Nishada (tribal), Chandala (“untouchable”) or a brahmin equal to one another if they are devotees of the Lord. None of these ever enter purgatory. (Garuda Purana khanda 1. adhyaya 230;49)

Gītā chapter 9:–

samo’haṁ sarva-bhūteṣu na me dveṣyo’sti na priyaḥ | ye bhajanti tu māṁ bhaktyā mayi te teṣu cāpyaham || 29 ||

I (Krishna) am the same to all beings; to Me there is none hateful or dear; but those who worship Me with devotion abide in Me and I in them.

api-cet sudurācāro bhajate mām-ananyabhāk | sādhur-eva sa mantavyaḥ samyag-vyavasito hi saḥ || 30 ||

If even the most sinful person worships Me with devotion to no other, he must be regarded as righteous, for he has rightly resolved.

kṣipraṁ bhavati dharmātmā śāśvacchāntiṁ nigacchati | kaunteya prati-jānīhi na me bhaktaḥ praṇaśyati || 31 ||

Speedily he becomes righteous and obtains everlasting peace, affirm on My behalf, O Kaunteya, that My devotee never perishes.

Itihaasa and bhagwad gita allows spirituality for dalits (outcastes)

Now some may show some verses from manusmriti, and Would tell me that manusmriti contains hate verses against dalits etc.

But you forgot that manusmriti is a dharma shaastra (law book) which was been edited by various pandits over time. So the manusmriti which we have now is very much adulterated .

So when dharma shastraa and itihasas contradict vedas should be taken into authority.

Quote from veda
yathemāṁ vācaṁ kalyāṇīṁ avadāni janebhyaḥ | brahma rājanyābhyāṁ śūdrāya caryāya ca svayāya caraṇāya ca ||

Just as I have revealed this salutary auspicious teachings to all humans, so should you. I have revealed the Vedic truth to brahmins, kshatriyas, sudras and Aryas, to personal servants and to the lowest of servants (araṇāya) also. 
(Sukla Yajur Veda 26:2)

So according to this verse everyone is entitled to and eligible for Spiritual Knowledge.

And B. g clearly states that the varna is not by birth that is by nature.
So one should not discriminate any person as a shudra, brahman Or kshatriya based on birth alone.

I (myself) born to shudra parents but my Guru is a brahmin and he generously gave teachings to me.

Same way all should follow it and do no discrimination as shudra Or brahmin thus it would help our country to become a better nation to live.

It's true dalits were treated badly since ages but you have to understand this has nothing to do with scriptures.

Vratyas ( failed brahmins) took advantage adulterated dharma shastra and treated dalits and shudras badly.

It's necessary that we condemn such people from our society and show them the mirror of shastras .

One should read scriptures before criticising it.