So before I get into this topic there are some things to be taken in consideration. There are assumptions that I have come to based on my observations of human behavior on various forums, on how fandoms work and the behavior of different individuals in different places and their intersection.
The alt right is a conservative political movement that emerged on the internet specifically in the United States and is characterized by opposition to the mainstream politics and the use of online forums and blogs (reddit, 4chan) to desseminate incriminating information antagonistic to minority groups.
Now these folks are easily found in the manosphere, in Ben Shapiro and Jordan Peterson's comment section or just trolling on the internet. These are mostly white men who are resentful of the progressive movements such as feminism or anti racism movements. Conservatives tend to have vested interest in upholding the hierarchical hegemony and they lash out when they feel it shaking (wrongfully).
How do solo stans come into this? Their behavior. I think these are young people who are increasingly swayed by reactionary movements such as the above and turn to conspiracy theories about companies and fandoms that make no sense. Point to be noted: kpop industry and companies are notoriously exploitative and a lot of times there are legitimate concerns which fans raise their voices against. Then there are times where things just don't make sense.
Let's take a look at the behaviors the alt right and solo stans have in common:
1. The same isolationist, mantric way of indoctrination
2. Engaging in feedback loop arguments
3. Accusations with short, quippy, reactionary takes (you are anti-member! (their way of saying shut up liberal))
4. Not taking longform, detailed and logical arguments and
5. Being prone to conspiracy theories.
Ofcourse not all solo stans behave the same. Some are just casual fans who like one or two members. I am talking about the crazy ones, the freaks. Now ofcourse solos are not as dangerous but there is an observable pattern in their behaviors.
There was some data on solo stan trends on Twitter recently and three countries came at top: Saudi Arabia, India and Brazil. Now these are countries which have quite conservative values in their societies. India and Brazil currently have a red wave going on.
Anyways this was just me psychoanalyzing solo stans a bit. You can disagree ofcourse.