What is a Commie or Communist?

I have noticed that when ever I ask a intelligent question that makes a person thing twice or think outside the box I get called a Commie Jerk or a communist. From studying history in my school I have seen that when ever someone challenged the government for the better they were labeled a communist. Ex in the 1960s segregated south many Whites that came down to assist in the efforts for change were labeled Communist. I don't know what it is exactly, but from my reading they never sounded like bad people at all and if it means to stand up for whats right and challenge the system for the better than I may wear the label proudly.