This is the big problem with both the massive scale of certain businesses, their extensive interweaving with government, and of course monopolization.
What I'm asking is if we as a public really want our payment processors to be making these moral judgements? That doesn't mean I think they should be compelled to do anything, but I certainly think it's cause for concern, and call for an alternative that IS willing to behave as a neutral party. I don't want the noise of what is effectively a pipe to be making arbitrary political judgements when deciding what is allowed to pass through.
Now, publicly funded banks, that's a different question. I absolutely expect neutrality within what is legal from our government institutions.
If this action was completely unprompted, sure, but I think we're talking about payment processors choosing not to associate with people who have already been the subject of boycotts on their previous platform.
A better example would be WikiLeaks which enjoyed a fair amount of public support at the time Visa etc declined to process their payments, as we have reasons to suspect that the pressure on Visa to do this may have been from the U.S. Government.
By contrast, there have already been numerous public protests against people hosted on the SubscribeStar platform.
I'm pretty sure that if you're in position of quasi-monopoly, it should be illegal
See: AT&T after "we" did, Microsoft after "we" didn't.
Apparently we do, otherwise they wouldn’t be doing it.
Outside of a standard set of specific reasons for which it is agreed to be illegal to refuse business (race, sex, orientation etc..), no business is supposed to be able to be compelled -by the government- to associate or transact with another. Instead, boycotts are used by the public themselves (rather than via government strongarming) or by company-to-company action to persuade companies to adjust their behaviour to meet expectations of what is ethically appropriate.
In arrangement, the expectation is not that companies are 'neutral' but that they are sufficiently moderated by public will. This freedom not-to-transact is what allows things such as boycotts of Apartheid South Africa, boycotts of companies that abuse their workers or run sweatshops etc.
There are plenty of ways to rearrange things outside of a Capitalist model, but once you decide to have Capitalism but 'prevent boycotting on political grounds' you're basically suggesting that Capitalism ought to be stripped of one of its extremely few mechanisms for ethical feedback. The implications of that ought to scare you.