If you are left (I am not, but I have observed it) and you agree with 90 per cent of the ideas of some group, but disagree on the remaining 10 per cent, they will turn on you in fury, denounce you as a traitor, hate you more than an actual opponent. Deviation from orthodoxy is a capital sin.
(This is not new, see how Trotskyists were extirpated by their Stalinist comrades 100 years ago. Heresy is simply not tolerated.)
The right wingers of today are a lot more capable of building a bigger tent, at least right now. Personally, I am somewhat rightwing, but very secular, as usual in Czechia. I still get invited to Christian events even though they know that I am not a believer, and they won't grill me to convert.
The same can be said about the right, but you are correct, infighting is stronger on the left.
But...
Orthodoxy (or better: tribalism) is actually stronger on the right, the key difference is, the right has less political complexity to argue over. "Our pure native culture will fix our problems and the other left outgroups must be suppressed" is pure identity politics, which is imo the core of the right.
The left has, tribalism aside, at least identity independent topics like wealth distribution. Which, unfortunately, threatens the existing power structures.
I can confirm the left ostracizing their own. It happened to me too, but i still consider myself left, because my political ideals are based on more than a group membership.
I think you underestimate the complexity of the right. It is not just secular nationalists all the way down.
First, there are still religious people there, and this very wing is splintered among several groups at least. Famously, many Catholics including JDVance were in a value conflict with their own late Pope Francis. The actual religiously educated people tend to be very good at writing, because the schools that they graduated from are good at teaching persuasion.
Second, there are libertarians, not very numerous but somewhat influential, especially in tech circles.
Then, there still are some trigger-happy neocons, nowadays marginalized, but they may yet come to the fore in case of a bigger war that directly involves the US.
Then, there are reactionary types like Curtis Yarvin, who dismiss any nationalist ideas as blind alley of "demotism".
Even the practical question of "how many people from which country should get a visa yearly and under what conditions" will hit enormous ideological differences in the right-wing tent.
To me, religious people, simple racist and libertarians all suffer from a identity-based cognitive bias. "Our groups or my well being is the ideal to project onto the nation/world." (Neocons dont fit in here, i have to admit. Maybe its abuse of power pleasing the monkey brain, but resulting wealth certainly too.)
I think self-withdrawal is more frequent in left leaning individuals for this exact, more unbiased/intelligent/educated reason.
But you are correct again. There is a lot of complexity on the right, if you look deep enough. But this depth does not cause as much infighting compared to the left, because, again: tribalism taking over higher order reasoning.
If you are left (I am not, but I have observed it) and you agree with 90 per cent of the ideas of some group, but disagree on the remaining 10 per cent, they will turn on you in fury, denounce you as a traitor, hate you more than an actual opponent. Deviation from orthodoxy is a capital sin.
(This is not new, see how Trotskyists were extirpated by their Stalinist comrades 100 years ago. Heresy is simply not tolerated.)
The right wingers of today are a lot more capable of building a bigger tent, at least right now. Personally, I am somewhat rightwing, but very secular, as usual in Czechia. I still get invited to Christian events even though they know that I am not a believer, and they won't grill me to convert.