Blocking them will just serve to isolate them more. You don't solve problems by closing off everyone who disagrees with each other into a thousand little bubbles.
Yeah but they're not looking to converse they're just looking to disrupt.
When you argue, you are either arguing to convince your opponent, your audience, or yourself. If your opponent is not willing to budge on their ideas, well, then you're pissing up a flagpole.
They have the option to do it and they did. The fediverse was made exactly for this situation and its nice it's like this.
It's not 'how' it should be running, it's more of respecting all others choices: you don't tell people what to do. Simple.
That move will tell you more on this community, than all the effort they could deploy to convince more people into their delirious system.
They weren't engaging in good faith political discussion. They were shitting in their own hands and flinging it at people who weren't interested in being covered in their shit. If you want to be covered in their shit you can create an account on those instances just as I can choose not to.