If we change our perspective, many things which don't make sense, suddenly start making a lot of sense. One example, is the unusual collaboration of the radical left, Islam and Christianity in India.
Indian Left supposedly represents rationality, logic and Nehruvian-style "scientific" temper. They are supposedly against superstitions. Yet they collaborate with Islamists and Church - both being religious institutions and the very embodiment of all things backward, unscientific and primitive.
The answer is right in front of us - we just need to ignore know categories of religions, social science and humanities, and instead apply a common-sense based framework.
What is the aim of communism/ left?
To ensure social and economic scientific justice for all humans across the globe (a very noble aim, indeed). To achieve this, all humans must subscribe to the ideology of left - both politically as well as socially. However to make humans subscribe to this ideology there must be violence and revolution, till the rich/ bourgeoisie/ elite/ religious power centers are overthrown/ eradicated/ destroyed.
In India, since there are no major religious institutions (like Vatican), the enemy by default is the majority population of India, the 80% Hindus. Thus non-stop violence, blood-shed and unspeakable brutality has been part of the leftist rule in all parts of the world, and especially in India where the left uses judiciary, media, education system and executive to subvert the Indian state which it intentionally equates with Hindu Rashtra.
What is the aim of Islam?
To establish world "peace". For "peace" to prevail, everyone in the world must necessarily be a Muslim and submit to the will of Allah. But for that to happen there must be violent and bloody war (jihad) undertaken by jihadis/ Mujahideens - whether physical, economic or psychological - until all non-believers (Kafirs) have either accepted Islam willingly, or been forced to convert or have perished.
In Indian subcontinent, the Kafirs were and continue to be the Hindus. Thus non-stop violence, blood-shed and unspeakable brutality has been part of the Islamic rule in all parts of the world, and especially in India. Even today they very effectively use judiciary, media, education system and government to peddle the "minority" narrative, grab resources, mock any assertive majority as "Bhakts"/ radical Hindutva-wadis while at the same time playing "victim" similar to left post-modernists, minorities and subalterns.
What is the aim of Christianity?
Not unsurprisingly, Christianity is no different. The aim of Christianity is to "save" all humans. All humans are born sinners, due to the "Original sin" of Adam and Eve. Jesus Christ died at the cross to save humanity from their sins. Thus to be saved all humans MUST accept Jesus and his "good news" irrespective of whether they want to be saved or not. But for all humans to accept there must be violence - till the time natives either die out or accept Jesus, whether willingly or unwillingly.
In Indian subcontinent, it is again the Hindus who need to be saved. Thus non-stop violence, blood-shed and unspeakable brutality has been part of the Christendom in all parts of the world, and also in India. Whether it was the British Raj brutalities (Protestant) or Goa Inquisition (Catholic) or the way Indian Christians supported Pakistan during partition. Today west (and implicitly Christianity) is associated by default with science and progress and the Christian groups use it to their full advantage. They play the victim card at every opportunity while they continue to abuse extra-ordinary minority rights already afforded to them.
For a Hindu, Left/ Communism = Islam = Christianity
Thus from this perspective we see a surprising similarity between Left, Islam and Christianity.
In all these 3 ideologies have one Supreme Being - God, Allah and State. They all have a messenger - Jesus, (He who shall not be named) and Marx. They all have one Holy Book - Bible, Koran and Das Kapital. And in India they have one common enemy - Hindus.
For a Hindu therefore, Leftism, Islam and Christianity are EXACTLY the same ideologically and in terms of outcomes, although the methods employed may be each group may be slightly different.
It is therefore no wonder that they collaborate with each other.