The only unity to leftism - which now rules the world - is based upon negation, rejection, opposition; and this is what brings leftism (over time) into cooperation with the agenda of the devil.
Leftism is 'the party' of those whose bottom-line ideology is oppositional - because pacifism, abolition, socialism, feminism, antiracism, environmentalism, healthism and all the rest, are oppositional in nature: none aim at any particular state-of-being or -society.
Of-a-piece is the usual leftist conviction that one is a victim, and/or works on-behalf-of victims: victimhood is just another negation.
But the ultimate negation of leftism is the rejection of all that is divine, spiritual, eternal... Leftism is rooted in atheism, denial of the reality of the spiritual and the soul, denial that reality is created, denial of any purpose to creation.
Therefore leftism is necessarily incoherent - because to deny all these is to deny any possibility of meaning and purpose, to deny any possibility of coherence and understanding. For leftist materialists; reality is understood to be merely an outcome of material causes and/or randomness.
And for conscious allies of Satan; 'reality' is an arbitrary and exploitative construct of a deceptive, manipulative, selfish deity. Evil is therefore, of its nature, (like leftism) also oppositional.
But the (Christian) truth is that this world is in spiritual war between God and those who ally with God on the one hand - and who desire the salvation of Men's souls; and on the other, those who oppose God's aims, plans and hopes for whatever reason - and who desire something-other-than salvation.
God's party has eternal purpose and meaning; the devil's party does not - but is a (temporary) alliance of expedience between those who oppose God.
Each human or demon of the devil's party is ultimately 'in it for himself' (as he personally understands and values his self-interest) - and all alliances are therefore understood as contingent means to that end.
The alliance for-God is (by contrast) ultimately coherent, because it has purpose - and meaning derives from purpose.
'The opposition party' includes a multitude of heterogeneous motives against God - disbelief, belief but rejection, dislike, hatred, inversion...
Leftism grows by fomenting opposition, and by collecting-together those who oppose on the basis that it will (for now) aid their personal goals.
The many materialist (ideological) 'leftisms' tend, over time, to develop alliance with supernatural purposive evil; because both are oppositional and materialist leftism is thereby strengthened with a (typically unconscious) spiritual power and purpose. Individual selfish motivation is also strengthened by hope for power over others, and the desire to be part of a large and strong allied-bloc.
Thus the world of 2020 is dominated by a vast, heterogenous and incoherent party of leftism = evil-affiliation. That is, a party that defines itself by what it opposes - and what it opposes is ultimately traceable to that which is of-God.
Such a party cannot construct, create or even conserve: it can only lie, subvert, manipulate, torment, invert etc. because it has no ultimate positive purpose, and because the left-alliance is based only on shared-opposition.
Purpose is impossible in a senseless-meaningless determined-random universe...
And such a party as the left will therefore necessarily be negative and destructive in its operations and outcomes: such a party will always tend to converge with supernatural evil, and will tend towards more purely-evil forms of evil.