The problem is not communism per se, but the way it has been implemented so far. Meaning that it was like monarchy, with loads of corruption. Political systems don't have too many differences between them; it all depends on the implementation. E.g., I believe that the best political system would be a monarchy as long as the monarch was a benevolent one. Today's democracies are not really democracies, they just provide the illusion of the choice to the stupid masses.
BTW, in case you don't know, Cyprus -a EU member- has a communist party governing the country. But it's still a democracy and from discussions I've had with Cypriots, nothing much has changed. It's totally insignificant what you call the system, corruption will find a way to intrude in EVERY system. Communism in Eastern Europe just had much more corruption and oppression than the people could take. The "western", "capitalistic" type of oppression is more subtle - eg the bankers rule but the people feel like they can choose who among their employees (= politicians) will execute the bankers' orders. This is how things are in Cyprus today, but now they call it "communism". It makes no difference.
ETA: Communist countries of the past were EXTREMELY convenient for the more subtle, economical dictators of the western societies. They could point at them and scare the people with the "communist threat". They can't do that so easily anymore, now that China is actually more of a capitalistic economy and North Korea doesn't scare anyone.