They could have chose any analogy in the world, invented a new one, or just said "let one bad actor in and others will follow," but they did none of that. They chose to use an analogy where Hexbear users are compared to Nazis.
Try that analogy on someone at work, or in your family, or on a Jewish person, and see if they interpret it as "oh you're saying I'm a bad actor here."
I feel greatful that such extraordinary courtesy is being extended to me.
There is one specific thread (this one) where your opinion is not asked
Not asking for an opinion is not the same as prohibiting one from giving an opinion. Your mod spent a ton of time and effort writing a detailed, thoughtful post -- he certainly would have added "this should be a conversation for our instance only" had he only wanted opinions from your instance.
There is plenty of honest dialogue on the internet, but also a whole lot of, shall we say, reddit-style bullshit. As plenty of fediverse folks have discovered, if you come to Hexbear with the former, you'll get what you're putting out there. If you come to Hexbear with the latter, you'll get clowned on.
Some people will inevitably be hostile even to good intentions (just like some people will inevitably read good intentions where there are none), but that's common on any large forum.
The reason we're focusing on the propaganda angle is because it's very clear to us that the impulse to defederate is at its core a political one.
The clearest evidence of this is instances defederating from both Hexbear and Lemmygrad: a notably more polite and less active (but politically similar) instance.
It is not the tone or the volume of posts people don't like; it is anything that challenges the prevailing Western attitude that capitalism is good and communism is evil.
There is plenty of non-political content on Hexbear, too. Plenty of Hexbear users comment on non-political stuff there and elsewhere.
Political stuff is the point of friction because politics involves disagreements people really care about.