The rationale is the theory that having a diversity of viewpoints, including some that are dangerous or repugnant, is the best approach towards a robust civil society and intellectual growth. If you disagree with something you hear or read, you can ignore it, or you can criticize it, but banning speech causes two undesirable outcomes:
1) The speech will continue anyway, but not in the public eye, where it can be criticized
2) The popularity of an idea is different from the correctness of an idea. It has happened many times that an unpopular or even heretical idea has turned out to be right.
Almost certainly these people are no Galileo. But this approach to free speech is intended to protect the Galileos of the world. It should be kept in mind that talk of revolution in the U.S. during the late 1700s would have been considered extremely dangerous and repugnant by many as well.
Private businesses and lay people not wanting to do business with you is fundamentally different from official prosecution. I will gladly fight for any group's protection from governmental over reach; I can't even begin to understand the rational behind choosing "private businesses can't have moderation" as the hill you choose to die on.
This philosophy is as old as the university and modern science. It is certainly no younger than the "free speech, but not consequences" argument, which I read as a thinly-veiled way to threaten unpopular views with unspecified "consequences".
> "private businesses can't have moderation"
I wasn't arguing that they can't. Only that it can be unwise and a net negative for our society for them to choose to do so. I would draw a distinction between trolling/spam and someone honestly espousing an unpopular view.
It is true, some kind of filtering is needed, because there's too much information for any individual to absorb. The question is, who (if not me myself) is doing the filtering and what are their incentives? dang's incentives are aligned with mine: good-quality technical discussion, and people aren't blacklisted purely for espousing unpopular views.
The incentives of corporations are not. Google, Facebook, and in this instance, Namecheap, are presumably taking these actions to safeguard their image and maximize profit, not to actually make their users maximally informed. There is a conflict of interest here.
Finally, I think all this becomes much more important when it comes to political speech, because people have a marked tendency to want to shout down, ignore, misrepresent, or otherwise not engage with political views that make them uncomfortable. Look how the media misrepresented the Damore memo. I take no position on the memo itself, but do assert that people are better off knowing actual arguments from all sides, rather than side A blacklisting side B and then giving strawman representations of what B thinks.
It's impossible to rationally debate ideas with no rational foundation; extraordinary claims require extraordinary evidence not calls to physical violence or pronouncements of superiority. A world in which "whites are the master race" is just an unpopular view that we should welcome as opposed to an unfounded assertion backed by no evidence is not a world in which any "net positive" has been added to society. When the burden is put on rational people to offer counter arguments as opposed to the extremists to offer evidence rationality loses every time; just look to vaccines and climate change.
I'm in medical research. Do I think antivaxxers should be able to publish in medical journals? No (unless they performed an experiment that passes peer review, etc).
Do I think they should be able to run their own websites, have nonviolent meetings or rallies without losing their jobs? Yes, I do. Even though antivaxxers are doing far more harm than neo-Nazis are.
Also, "scientific/academic consensus" and "rationality" are not synonyms.
That is literally what OP is about.
Now if it were the ISPs handing this ruling we'd be on the same page, but it isn't. There's no freedom of speech argument for "right to demand services without restriction". Same way a restaurant will turn you away if you show up with "no shirt, no shoes". Namecheap is using the freedom of speech of it's leadership in saying "Nazis and other groups that incite violence are not groups we want to host".
Right for service totally without restrictions, no, but "viewpoint-based discrimination" or other types of discrimination are a separate legal category for a reason. "Shirts and shoes required" is different from "whites only" (or, for that matter, "liberals only") on a restaurant door. We allow the former but not the latter, and I think that's reasonable.
See, even calling them Nazis is stupid. They are nowhere as dangerous as Nazis. Nazis conquered Europe in what? A year? Killed 6 million Jews, etc. 12 million Russians. These people are pissed off at life and where they are, and are looking for an excuse that doesn't involve self examination of their own choices. But they sure as hell ain't Nazis.
Turns out, most companies don't want to be associated with Nazis; shocking I know. And, as Nazis are not a protected class in the United States, it's fully within their rights not to do business with them.
It's easy to say "let's all support a version of free speech that's never existed because we believe in the ideology" when these groups aren't targeting you. It's a bitter pill to swallow if you happen to be Jewish, Black, etc.