Leftists reject everything that emanates outside of their Party. Only things that come from the Party can be embraced as "good".
For instance, Elon Musk is hated by the left because he has helped the American people to eliminate astronomical amounts of fraud and waste. They would have loved Musk if Biden had been the one to ask Musk to audit the federal government.
Musk was instrumental in safely returning the stranded astronauts to Earth. Of course the astronauts probably could have returned much earlier except that the Party was opposed to it because it would have reflected favorably upon Musk.
For leftists, everything revolves around the Party. Anything that might detract or cast the Party in a less-than-positive light must be rejected.
Dr. Fauci contributed to the unleashing of a pandemic but since he's a leading member of the left's church, he is revered! Millions dead and trillions in destroyed wealth? No problem!
For these reasons and more it is impossible to engage with leftists. There can be no common ground because their love, loyalty, and devotion are to their Party. Truth, facts, and what's "good" for poor and middle-class Americans is completely irrelevant to them. So, no, it is not possible to find common ground and unity with them.
Both religion and politics address similar topics, in answering questions such as what is good and acceptable behavior and what is not within society, and what should be done about it if anything? Both focus on how people should live their lives and what choices are not acceptable to help preserve a civil society.
It is no wonder then how the two have become intertwined over the years. It used to be that kings declared themselves a god, but when that no longer had appeal, they then claimed to speak for God, but when that lost appeal, they later claimed that there was no God, thus making themselves the undisputed God-like authority once again.
And today? Today they are trying to create their own god with AI. So, instead of seeking an all-knowing God they will create an all-knowing computer that will tell society how it is best to live their lives, because it will be sooooo much smarter than all of us combined.
I view this as the final step before God himself returns to set things straight.
You are right about the Left, it is in many ways a cult, but you should also understand that with a dose of humility as pretty much anything can turn into a cult. That is because the tail, tail, sign of a cult is when the focus is a personality or an organization, or soon to be AI instead of the one true God.
One day Jim Jones is a regular pastor, the next day he is taking his flock to Central America because he fell in love with Marxism and then had his congregation drink the cool aid.
But I think the parrot in the cave showing us just how cult like the Left has become is the growing number of people who are forsaking their friends and family who refuse to vote democrat. That is because the number one rule for a cult is to try and have their members try to convert their friends and family to the cult, and if you are unsuccessful, you must break ties with them forever.
I really only see this with the Left.