Well, the difference is that being a (neo)Nazi is, rightly, illegal in Germany. Being a Communist (or even a Stalinist) is perfectly acceptable, and even encouraged from the top, in Russia.
Not exactly. What is strongly encouraged is supporting Putin's cult of personality. And Russia (especially Moscow) is more along the lines of crony capitalism these days.
They do try to wrap it in nationalism and appeals to history ("back when the motherland was strong!"), but it's transparently about enforcing the oligarchy.
There's quite a bit of rehabilitation of Stalin going on, and a lot of "and if somebody was executed, well they were the enemy and deserved it". Reading Russian forums can be quite "entertaining" in a way lately.
Well, it is traditional for tyrants and despots to rewrite history to suit their goals. And it does make sense to attempt a restoration of Stalin's public image.
He was objectively the greatest leader in the history of their country/union, with a massively powerful cult of personality. To paraphrase from a popular series of books, "after all, [he] did great things – terrible, yes, but great."