I think socialists should probably stay away from bitcoin if that is the case, namely due to how difficult it is to tax. Especially if people begin trading bitcoin over the tor network.

By investing in or even mining bitcoins, socialists would be contributing to the decline of socialism. You'd basically see a return to the early days of the US where they relied upon the taxes of sales of certain goods. Services would be unable to be taxed effectively, and income for large corporate entities would be hard to tax (which would be a good thing IMO as corporations as it is don't really pay any taxes - they just push the expense on to the customer.)