I was right afterall. Pro whole-DG forum has finally accepted that the the Devi of DG is none other than Adi-Shakti. I will some part quote here from their article. You can read the whole article over there.
" In 48 verses, the character of 'Chandi' has been described, but here Chandi is not a revered Devi of Hindu or any Tantric faith. Chandi is that force of Akal Purakh which, from the beginning of time, has been active in destroying impious forces. This force is also the sword, and also the blade. It is one such sword, the rein of which is diverse and widespread even in far off lands, in all four corners; therefore, it is inappropriate to group and limit this maternal-force to India and its religions. It is Jogmaya (the force with which the universe is created), Saraswati (the Devi of knowledge) and mighty Bhawani. It has brought about the existence of Brahma, Vishnu, and Mahesh....
In above verses, we can see that this force manifests itself as the source of creation of not only numerous Devis but also the three main Devtas. In no way it is a Devi of Hindu faith, for it is the creator of this entire universe and also of people of different faiths and beliefs. Not only that, the spread of different faiths and religions is its own expansion. All those who live in remembrance of Akal Purakh are created by this very force. It has got extremely horrific appearance and it is also like an extremely beautiful, virgin girl. These paradoxical forms presented above are worth contemplating on. Here, instead of being a Devi, the source of creation, or the Primal Force, it takes on the form of a female. The protagonist of 403 Charitars is a nymph of ugly proportions whereas the protagonist 'Baala' of 'Sabudh Baach' is pure and chaste girl that is decorated with pure qualities; she is someone whose chastity can never be violated."
If you have spent time reading whole of it, you will understand that the source strength of Sikh warriors and Guru Gobind Singh and that of Khalsa was Adi-Shakti. If you have patience and desire to learn more then read this too below.
" The Chandi of Charitropakhyan is the source of creation, the Devi, the force of Maya, slayer of demons in the form of deadly weapons, and in the form of cultured and virtuous woman too. Not only it is the destroyer of demons like 'Sumbh-Nisumbh', 'Chand-Mund', 'Rakhatbeej', etc.; it also is the source of the enunciation of all four Vedas. This primal force is also the creator of all struggles and conflicts in this world. It manifests as 'Narsingh' and destroys the demon 'Harnakash'. This force also takes on the form of brave men and courageous women. It is creator of this universe and also its destroyer. It takes on the form of Ram in order to destroy 'Ravana' and it also takes on the Avatar of Krishna for the destruction of demon 'Kans'. In these situations, it does not remain the primal force of Shaakats and Tantriks; instead it emerges as the constructive force of Akal Purakh Waheguru Ji, the mention of which appears in 'Anand Sahib' Bani of Sri Guru Granth Sahib Ji Maharaj:
ਸਿਵ ਸਕਤਿ ਆਪਿ ਉਪਾਇ ਕੈ ਕਰਤਾ ਆਪੇ ਹੁਕਮੁ ਵਰਤਾਏ ॥
Similarly, there is also mention of this force in Guru's Arjan Dev Ji's Bani 'Maaru Di Vaar'. Here, we are told of Waheguru Ji's dominance and command over this force of creation. In 'Devi Bhagvat Puran' too, the Devi is the force of creation – 'Namō Devai Parkaritai' (ਨਮੋ ਦੇਵਯੈ ਪ੍ਰਕ੍ਰਿਤਯੈ). In reality, the Devi of Hindu Shaastras is both the force of 'Sankhai Shaastar' as well as the force of God. It is present as the force of Maya of God, above the forms of wife of Devtas and those of numerous Devis. This quote from 'Devi Bhagvat Puran' verifies the above stated fact - "Brahma asked: 'Are you male or female?' To this, Devi replied: 'The One and Only truth is Brahm, there is no difference between us. Whatever He is, I am that. Due to ignorance, people differentiate between me and Him. Only that Brahm is supreme, He is indestructible and has been present even before the beginning of time (Snatan). During the process of creation of this universe, it takes up countless different forms and that is when we both appear different, like a reflection in the mirror. At the end of the universe, I cease to exist as a male or female.... ". This Devi, the force of Maya, is definitely different from the Devi that is worshipped as the wife of Devtas. In some areas of the Tantric faith, it appears to have superiority over the male or Shiva. According to Sri Guru Granth Sahib Ji Maharaj however, this force performs its actions as per the Hukam of Akal Purakh Waheguru:
ਹਾਠਾ ਦੋਵੈ ਕੀਤੀਓ ਸਿਵ ਸਕਤਿ ਵਰਤਾਈਆ ॥
ਸਿਵ ਅਗੈ ਸਕਤੀ ਹਾਰਿਆ ਏਵੈ ਹਰਿ ਭਾਈਆ ॥
(Ang 1096, SGGS Ji)
The girl 'Baala' of Charitropakhyan is also shown to perform her actions within the sweet Hukam of Waheguru, although absolute victory in 'holy war' initiated by the male is depicted to be impossible without 'Baala' bursting into the battle scene. To win over 'Kaal-Purakh' in husband form is her penultimate goal. In this case, she is the soul-bride and Kaal-Purakh Waheguru as husband. In contrast to the indecent and ignominious union of male and female that was mentioned in the dialogues of minister 'Bhoop', this establishes the male and female union of limitless purity and pulls mankind out of the sorry state of that disgraceful situation; and even though narrative style may appear to be different from that of Bani of Sri Guru Granth Sahib Ji, the similarity in the levels of purity depicted in its final form is unparalleled and inseparable. "
All in all the existence of such force of nature was always denied by the pro whole-Dg group. They always claimed Durga is creation of Akal Purakh, Chandi is creation of Akal Purakh, Krishna is worm, Ram is fake etc etc. They claimed Dg eulogized only bravery of various avtars, nothing else. But left out the primal force, mother force, out of discussion.
Now they have admitted the real link between Akal purakh and the world. Adi Shakti. Only if the Sikhs learned Hindu scriptures they will realise their true self. Just like Nirmalas and Udasis did, after learning Hindu shasters. In the light of this whole concept, the Sikh Gurus are a small part in this whole drama, just like Ram, Krishna etc. Ram came to destroy evil in form of Ravana, Krishna came to destroy Kans and Kauravs and Guru Gobind Singh came to destroy Mughals ! And another mission of tenth Guru was to make people realise the fakeness of Ram, Krishan and that of himself. Everybody dies in the end. Mortals ! Only God remains and the Power, Adi-Shakti, which sustains the world. And this power is source of strength of DG. Same as in Shaktism, albeit with some variations but that happens with every belief system. What matters is in Both DG and Shaktism, source of creation is Adi-Shakti, God is there but plays no active role. Both have to turn to Shakti to sustain.
Now all that is left for Sikhs to realise and pro whole-Dg to reveal is the supreme entity Brahman.