I think the pandora's box you're opening is about sociology and psychology. Among the religious there is the divide of conservatives and revolutionaries, and finally within denominations there is a divide of conservatives and revolutionaries.
When you say "right wing and leftist" these terms define conservatives and revolutionaries. This kind of sociopolitical nature goes all the way down the family unit or any social organisation not gathered by synonimity.
Why are conservatives frequently religious in their presentation? Because any conservative seems religious to a revolutionary, being often synomynous with traditionalism to all appearances.
For example, many of the things viewed as religious dogma by revolutionaries of conservatives are quite plainly expressed as existential observation. My experience, where it differs from yours, is your religion if you are to adhere to it without understanding it. Not the same thing as calling it my religion.
As you allude between cultures, and indeed between demographics, perceptions will differ and hence misunderstanding is commonplace. So we have politics, because whilst you have the right to live as you will in a lawful manner, so do I and yet our manners and celebrations are entirely different.
Our definition of right and wrong, responsibility and obligation will often be entirely different.
Here's what we can wind up with. You call wrong, right and matters which are none of your concern, wrong, as a nation (both in foreign and domestic policy). But this cannot be explained in spreadsheets, it falls in grey areas of legal systems. Hence many political movements are openly concerned with moral culture, and probably the only political movement which even attempts to deal with such a thing, and the only argument such concerns have, is religious or sounds very much like religion.
The proverbial political concern of arriving at a dictatorship like Hitler's Germany for example, is strictly conservative in nature. The US Constitution could be said to have been mooted in a fit of conservatism. Want to break new ground? Could wind up with another Stalin. Pure leftist is to slide the entire structure off the table in a sweeping motion and invent new ideas.
But then...new ideas always come from primordeal inspirations, do they not? The most ancient conservatism of all. Could it be revolution at its very core is the beating chest of an ape attempting to challenge its bull male?
The epitome of right and leftist respective policy staring at each other across the table, were Hitler and Stalin in fact very far removed from each other at a grass roots level? Methinks the only change was who/why genocide.
Right and leftist is a constant and as you said relative. Specific context and considered response irrespective of sentimentality is going to win the day, but there is always something else which comes up, some piece of corruption to mute honesty. The economy, or public order, etc.