Earlier quoted context omitted.
Because of the incredible harm to humanity done at the hands of communists over just the past 100 years alone
When you buy a beer for your friends at a bar and maybe next week they buy a round, that's communism. Communism is a central part of western society. China, the USSA and Cuba were never communism. They varied between heavy socialism (also a pinical of all high income countries: roads, trains, parks, police, fire, airports) and fascism. A lot of people who just go on about communists, today, in 2016, seemed to have no…
Buying beer and sharing with friends week after week is a good example of capitalism, as the bar owner is profiting so much from you and your friends buying all this beer.
Communism (of the Marxist variety) would be you and your friends being allocated the same amount of beer by the state, which owns the beer (along with all goods), and deals out the same amount of beer to everyone, regardless of what they do (i.e. what would have corresponded to their class).
I suppose there is another kind of communism where you and your friends live on a commune and some grow hops and some grow barley and some are in charge of fermentation vats and all just relax and drink their beer after a long day. That is, until the tax man cometh...