Hari OM
Sri Gurubyoh Namah!
Sri Matre Namah!
No one has eligibility or right to question the belief or proclivities of a devotee or an individual based on his or her perspective and conscience. As per Vedic scriptures God or Bhagawan is someone who fulfils six qualities or attributes (complete splendour, virtue, glory, opulence, knowledge, dispassion) together known as bhaga:
aiśvaryasya samagrasya dharmasya yaśasariśrayaḥ jñānavairāgyayoścaiva ṣaṇṇāṃ bhaga itīraṇā [VP – 6.5.74]
Meaning:
Complete splendor, virtue, glory, opulence, knowledge, dispassion – these six are known as bhaga.
So from scriptural point of view Shirdi Sai baba or GF (or Buddha or Mahavira or Gurunanak or Jesus or prophet) may not be God themselves for some people but scriptures also say that Guru is God Himself. We all know this from Gurur Brahma Gurur Vishnu.. verses. And as per the scriptures, the devotion, reverence, behaviour and respect towards a Guru should be similar as one would respect, treat and behave towards God.

From Upanishad:
yasya deve parā bhaktir
yathā deve tathā gurau
tasyaite kathitā hy arthāḥ
prakāśante mahātmanaḥ
“Only unto those great souls who have implicit faith in both the Lord and the Guru are all the imports of Vedic knowledge automatically revealed.” (ŚU 6.23)
And the scriptures also state that God realized souls (sages) who know Brahman become Brahman:
brahman vid brahmaiva bhavati [Mundaka Up. – 3.2.9] mayātma-bhūyāya ca kalpate vai [SB – 11.29.34]
Meaning:
Knower of Brahman becomes Brahman himself.
So by this definition, if someone is a God realized soul, then he is a God. But the Godly powers and opulence may or may not be present in Him as it is only a definition basing upon the Godly bliss he experiences.
(bhogamatra samlingyacha [BrSu – 4.4.21])
Bhishma said in Mahabharata Santi Parva Section 132 that a man
“is said to be conversant with duty, who knows duty as depending on all four foundations”. These four foundations of duty are (1) as laid down in the Vedas (Srutis), (2) as laid down in the Vedic scriptures (Smritis), (3) as sanctioned by ancient usage and customs and (4) as approved by the heart or one’s own conscience.”
Guru is not equal to God, Guru Is the God. The question of equality comes only when there are two different aspects, but Guru and God are non-different. So the Bhagavatam says:
acaryam mam vijaniyan navanmanyeta karhicit
na martya-buddhyasuyeta sarva-deva-mayo guruh [SB – 11.17.27]
Meaning
One should know the acarya as ‘Myself’ and never disrespect or ignore him in any way. One should not envy him, thinking him as an ordinary man, as he represents all the deities.
Thus whether a Hindu worships Sai baba or not is a matter of his conscience. Nobody can interfere in such a matter.
So even though one may not be God as per the first definition of Bhagavan above, he is certainly God for his followers and disciples. The power of the deity or a human comes from the belief, devotion and positive thought waves from devotees and the curing or healing powers of the Guru or a deity. A Guru or Acharya is a master who spreads wisdom and selfless love – the Divinity. A Sat Guru is an enlightened master who has become one with the source—the undifferentiated, self-effulgent, non-dual Brahman or the absolute consciousness.
While purity, maturity and wisdom are common in all —Gurujis, Satgurus, Pujjyas, Acharyas, Siddhas, Yogis and Swamijis, physical worldly detachment can be seen in Swamiji’s and Satgurus. Enlightening mastery, healing or curing power can be seen only in a Satguru. This comes either by Divine Grace and / or through the efforts of the Satguru in several births to attain that state.
Also one should not waste his time in debating or arguing about his/her beliefs or forcing someone to accept their beliefs. Remember it is the nature and game of the Mayic mind with its intellect, always trying to drive us crazy to get into such wasteful and absurd debates , arguments and fights to depart from the Wisdom and embrace grief of this Mayic world. We have to be very careful to avoid such thoughts, associations, talks or Dursanghs. We should never hurt anyone by our thought, word or action.
Also in Kaliyuga, to cross this ocean of turbulent material energy the easiest way is to hold the feet of a Sat Guru such as GF, Shirdi Baba, Ramana Maharishi, Kanchi Paramacharya and Sri Ramakrishna Paramahansa.

Sai Baba of Shirdi who lived 1838-1918, gave no distinction based on religion or caste. Sai Baba’s teaching combined elements of Hinduism and Islam: he gave the Hindu name Dwarakamayi to the mosque he lived in, practised Muslim rituals, taught using words and figures that drew from both traditions, and attained Samadhi at Shirdi. One of his well known epigrams, “Sabka Malik Ek” (“One God governs all”), is associated with Advaitha Vedantha of Hinduism, philosophy of Islam and Sufism. He also said, “Trust in me and your prayer shall be answered”. He always uttered “Allah Malik” (“God is King”). (Wikipedia)
The Gurustotram Says
Ajnyaana-Timira-Andhasya Jnyaana-[Aa]n.jana-Shaalaakayaa
Cakssur-Unmiilitam Yena Tasmai Shrii-Gurave Namah ||3||
Meaning:
(Salutations to the Guru) Who Removes the Darkness or Ignorance from our Blind (Inner) Eyes by applying the collyrium of the Light of Knowledge.
By Whom our (Inner) Eyes are Opened; Salutations to that Guru.
Sai Baba did open the inner eyes of millions of people. Those are all his devotees, but Sai Baba is a Guru who preached nothing but still taught everything. He never asked for a temple with millions of devotees visiting it every week. His grace has been a strong and positive influence in so many lives that the Gratitude flows in the form of Love, compassion and respect and idealizing of the Guru that is Sai Baba. Enlightening mastery, healing or curing powers of Satguru Shirdi Baba can be experienced by His devotee.
Religion is for the mind or Ego. Spirit is beyond that. Satgurus such as Sai Baba, GF, Ramanamaharishi Kanchi Paramacharya and Sri Ramakrishna are beyond the reach of Human intellect and its limited capabilities — in understanding the inner and profound truth of scriptures.
An either-or approach to religion (you can worship this, but not that; you can be a follower of this god only if you stop following that god) is the farthest possible thing from Hindu way of doing things. It is within the folds of Sanatana Dharma or Hinduism that places, rivers, animals, elements of nature, sages, saints, and Deities find worship. The infinite variety of gods and deities in Hinduism is a point of pride for Hindus everywhere.
Do not get deluded by Ignorance by listening to any misinterpretation of scriptures.
According to Vedic scriptures, the Guru is God Himself manifesting in a personal form to guide the aspirant. Grace of God takes the form of the Guru. To see the Guru is to see God. The Guru is united with God. He inspires devotion in others. His presence purifies all.

Religion is for those who are asleep. Spirituality is for those who are awake. It is preferred to be a spiritual fruit than just being a religious nut.
Hope it is clear.
Om Sai Ram!
GF’ Blessings. Om Tat Sat.