Did I make a claim that communism had been implemented on a national scale successfully? I think I made the exact opposite point, in fact, that it has not, and possibly cannot be implemented on a national scale successfully.
On the small scales, however, it does work.
And on the small slide towards communism, socialism, there are many governments that are perfectly stable with happy citizens that are quite socialistic in nature.
Moving towards communism is moving toward socialism, which is proven to work. What happens when you move toward naziism?
Errr, I typed that, and re-read your question, and realize that it didn’t really answer what you were asking. I’m gonna leave that anyway, and try to answer a bit better what I think you are asking, in that what communist governments did not start with a philosophy of murder and violence.
And to answer that, I’d say most of them. I mean, technically, all governments are founded on violence, there is no exception to that, I don’t think, ever (can you think of one?). The United States didn’t become a country through peaceful means. So, to condemn a government because it uses violence to get established is to condemn every government ever.
I do not believe, however, that many of the communist governments were formed with the philosophy of violence against their people, but instead were formed with the ideals that everyone would be treated fairly and equitably. Now, the way that played out, with people in charge being human, and humans being poor at wielding power without corruption, and part of the communist practicality requires that power be concentrated into the hands of a small number of people, I will agree, has not turned out well.
So, as I said, communism may be unworkable, and it may be naive to believe it can work on national scales, but it is not based on the philosophies of hatred and bigotry, as is naziism.
Which is ultimately my point. You can march with a communist, because you share the core ideals of fairness and equality, even if you disagree with that particular communist on their particular brand of implementation. You cannot march with a nazi without sharing the core ideals of racism, no matter the implementation of naziism you may think you want to bring about.
ETA: and strangely, I find myself agreeing with ZPG up there, in that another reason to use the symbols of communism against nazis is that the people carrying those symbols did more damage to the naziis than the those carrying the symbols of the allies did.