The reason people equate the Confederate Flag with the support of slavery is because they think the main reason the southern states succeeded was because of slavery. The Civil War was begun over the issue of Federal vs. State Government of these United States. The states believed that the Federal Government was taking more power, and control, i.e. taxes, than it was given in the Constitution.
Remember Texas was trying to become it's own country, and most of the western part of the U.S. was still to be settled. The flags of our states, and of our countries mean things.
To the south, honor, chivalry, independence. They were fighting for the right to be independent states within a larger union. Fortunately for us, and for the people enslaved at the time in our country, the greater good of becoming The United States of America won out.
The battle flag should be honored. People fought and died to make our country what it is, these were the birth pains of a Nation. Why not remember it as that. I think the heritage of the Civil war should not be forgotten, let the flag fly to remind us that at one point in time not all were free in American, and not all were created equal, lest we forget.