It is extremism if and only if refusing to negotiate with muggers also is extremism.
> trying to frame it as the world threatened by the sword of communism
Whether the world at whole is threatened or not I dont know (people seem to survive in North Korea), but leftists like you certainly threaten my income and my freedom. If you scheme to force me to give a part of the products of my labor to you, it is the same thing as forcing me to work a part of my workday for you. In my eyes, wanting to force people to work for you against their will makes _you_ an extremist.
> signals a refusal to enter any kind of debate.
If you carefully observe, we're already debating right now. But you seem to be more preoccupied with labeling your opponents as extremist, refusing to debate, etc, than with debating itself. Refusing to play the "let's meet at the middle ground" game doesnt imply refusing to debate at all. It just means your argument (communism is good, so gimme your stuff) is too nonsensical to make me accept even parts of it as reasonable.