How does shunning someone for their political beliefs help advance your own beliefs?

Seriously.

Refusing to professionally engage with someone due to private political beliefs will do nothing but strengthen the resolve behind that belief. Instead of stepping across the battle lines into your exalted realm of enlightenment, they will circle the wagons and reload the muskets.

What if Tolkien had refused to befriend CS Lewis due to Lewis' atheism? Lewis would've remained an atheist all his life. Instead, through their friendship, Tolkien brought Lewis over, leading him to write one of the most influential texts in evangelical Christianity ever published.

There's a lesson in there for absolutists.

I have a vague memory of some research recently (last few months) that showed it was nigh-on impossible to persuade most people of a contrary position to one they held. In fact, it helped to strengthen their existing beliefs.

But my google-fu/pocket-fu is weak and I can't currently find it.

You may be referring to the result that exposing people to evidence contradicting their beliefs actually increases the strength of those beliefs (older than a few months, though). Pop-sci level article at http://youarenotsosmart.com/2011/06/10/the-backfire-effect/

This doesn't reduce to "impossible to persuade most people of a contrary position." It just means that you have to employ methods of persuasion, i.e. rhetoric. This was obvious in classical Athens, when people heard news and discussed politics in public, but is apparently harder to grasp in our society.

You missed off "nigh-on" from before "impossible". It's an important qualifier.

Back then being or becoming Christian didn't mean an end to your career; perhaps some of this current hardness is due to the much nastier consequences of going against the mainstream?

Lewis' conversion was not due to a direct effort on Tolkien's part, but he woke up one day an believed (his words.) However, people who overplay the role of discussion in solving problems may miss the fact that a person may be influenced towards an opinion by exposure to certain ideas. What your words cannot do, time may do, with your influence as a driver. It is a well known technique to befriend someone in the hopes of influencing their opinion (you rarely can argue them directly into a differing opinion, as per Swift's dictum.)

Much of this wagon-circling is influence control or more caustically, hugboxing. If one never hears of a rational person saying things that are what is presently defined as 'racist', one can not make the association of 'racist' ideas being rational (be influenced by them.) Ergo why most people's reaction to some of these texts is 'didn't he learn not to be an a-hole?'

But the fundamental problem is that if some ideas which are considered 'racist' are in fact rational, and considered racist only because people are afraid of them, people who seek knowledge and truth would not want someone to close off this information from them, even if they ultimately decide the case is overstated.

Environments such as this work well when all opinions can be stated but none has the power to exclude. This condition is fragile and exists under tension, since many ideologies contradict one another harshly and some are designed to sophistically undermine thought to drive it towards their own ends.

It is however important to note that Yarvin's appearance here is not under the condition of him giving political opinions or having the power to exclude. One can only conclude weakness on the part of StrangeLoop's supporters, and if such ideas are even in their suggestion so much stronger than their own, they have already likely lost the battle.

In fact, it seems like their followers have tipped the apple cart on this one. Now everyone is wondering what Yarvin could be about that would get him banned?

Do you also feel the intense sense of extremely partisan, political divide in the US is desirable? Because that is what results from holing up in ideologically segregated communities where everyone agrees about nine-tenths of everything, and where one only encounters their political other in the form of a media caricature.

I do not think that the sorting of the population by politics is desirable, but I do think it is inevitable and that it presages a period of low-intensity conflict. America is not one place anymore. It has become a set of enclaves, and it's not just a left-right split. It has multiple dimensions: religious, economic, authoritarian/libertarian, racist/inclusive, etc.

That's just weird. I strongly disagree with some of my favorite people.