It's very disappointing that you cannot distinguish between "opposing views" and "death threats".
Let me try to help: one is not illegal so it should in principle be allowed on a platform that is seeking an honest discussion. The other is a crime and can be dealt withing the framework of the law. If the person commiting crimes is behind an anonymous identity, I think that's where the problem actually lies - perhaps the administrator should be compelled by law to disclose the real person behind the anonymous profile (is the Mastodon community against that)?! If what they've done is indeed against the law, then a ban is definitely justified (and may be required by law - i.e. we're back to the rule of law, not mob rules), no one will argue against that... but what I am against is banning people simply for having opposing views, which is what we actually see happening. Do you see people complaining that someone who commits crimes online should not be banned from anything? That's not my argument or anyone else's argument, so your response comes as a complete strawman.
I think you’re trying to make exceptions because the actual rhetoric and logic this leads to is distasteful. Using “well it’s illegal” is just shallow logic to differentiate speech that should or shouldn’t force people to expose to as is that people should be exposed to whatever they consent to be exposed to.
Frankly, if Alice is seeking honest disagreement discussion, Alice should seek to talk with people who consent to that kind of engagement with her, instead of chasing after Bob who would rather not engage. If Alice is having difficulty finding those people, maybe her source selection is simply quite uncommon; lots of highly controversial subject matter applies almost exclusively to small parts of the population, and a minority of that minority is generally available to debate on that subject.
I’m sure Alice can have spirited debate about toppings on pizza, a subject that a larger set of people are usually willing to disagree and discuss about. If she insists on trying to force a minority of a minority to debate with her, I think a friend group is fairly justified in defending Bob by ousting Alice, as Alice is unable to respect people’s basic boundaries like “can we change the subject”.
Let me try to help: one is not illegal so it should in principle be allowed on a platform that is seeking an honest discussion. The other is a crime and can be dealt withing the framework of the law. If the person commiting crimes is behind an anonymous identity, I think that's where the problem actually lies - perhaps the administrator should be compelled by law to disclose the real person behind the anonymous profile (is the Mastodon community against that)?! If what they've done is indeed against the law, then a ban is definitely justified (and may be required by law - i.e. we're back to the rule of law, not mob rules), no one will argue against that... but what I am against is banning people simply for having opposing views, which is what we actually see happening. Do you see people complaining that someone who commits crimes online should not be banned from anything? That's not my argument or anyone else's argument, so your response comes as a complete strawman.