Those are specific circumstances though and I don’t think any of these - law firms, internet hosting, etc reach that threshold.
AWS is one service. YouTube is one service. Twitter is one service.
Yes, they are big services - in most cases, the biggest service among their competitors.
They have stakeholders and financial incentives to not be associated with - or worse, seen as condoning - deeply unpopular or controversial political positions.
Why is it so easy to understand when it's a baker refusing to bake a cake for a homosexual wedding or a Christian-owned company refusing to provide birth control for their employees?
1. Should there be a bright-line rule - either enforced by government or strong social pressure - about whether people must engage in business with other people, and on what grounds they may discriminate?
2. Should there be a social norm that businesses should try to serve all customers where possible, for the good of customers?
Our society generally answers 1 with that you must refrain from discriminating on the grounds of deep personal characteristics and no otherwise. You cannot throw someone out of your bar for being black. You can throw them out for being drunk and picking fights. You cannot refuse to hire an employee who needs to take a few breaks a day to pray. You can refuse to hire an employee who needs to take a few breaks a day to hire Fiverrs to do their job for them. You cannot refuse to offer credit cards to ethnic North Koreans living in America. You can (and must!) refuse to offer credit cards to North Korean citizens.
This is a sensible position, because it balances the general right to freedom of association / the government not micromanaging your business transactions with the more specific individual rights to participate in society. I cannot change my race, and (we have decided) it's unreasonable to expect me to change my religion. I can (we have decided) change my competence, and I can certainly change whether I start bar fights.
We could decide otherwise, but I think the existing position has a lot of merit.
Number 2 is a more interesting question, but I think the norm of our society is that it should be answered by the free market. We expect that businesses want to serve as many customers as possible anyway because it's the most profitable. Should they decide that they don't want to serve certain customers, it's generally not the place of either the government or strong social norms to say, we wish to override your decision-making process and tell you what to do (apart from the bright-line rule in question 1). Part of the freedom of a free market is that actors are free to decide what to do on their own, including to make mistakes, and no central planning committee tells them what is best for society. We expect this approach will lead to fewer mistakes and a better society.
Again, I think this position has a lot of merit, and we should figure out why we want to change it.
Banks, especially the big ones, will always be bailed out in a crisis. We've just had a demonstration about a decade ago.
Financial services get very heavily regulated which imposes huge costs, so it is arguable that imposes a certain level of obligation on government. I think that’s a reasonable case, though I’m not entirely happy with the way it’s been handled in practice. It’s not a perfect world.