I never fail to be amazed at the sheer stupidity and ignorance of people when such a question is asked.
The fact that so many people are historically ignorant--as to what the Confederacy represented and what the flag represents--is clear from comments analogizing the battle flag to the swastika. Liberals are certainly much more akin to the national socialists (Nazis) that bore the swastika. Like their ideological ancestors, the liberals also believe in telling people what they can and cannot say, and of the various socialistic schemes that all socialists--past and modern seem to share.
The Confederacy represented the right to self-government--the same right that the people of 1776 fought the British over. The second war for independence (the War Between the States) was fought ONLY because the Southern people wanted to govern themselves and the Lincoln-led federal government wanted to act against the right to self-government, and force the Southern States back into a voluntary union. The mess that we have in the federal government today can all reflect back to those that were in charge of making war on the Southern States from 1861-1865. Federal income tax, the diminution of State power, the over-reaching federal government, trampling of individual rights---all started in 1861.
As to the fact that certain groups use the Confederate Battle Flag for undesirable purposes, those same groups (which are extremely small and are hardly even worth mentioning) use the stars and stripes in their little rallies. If you look at Klan rallies from the 1920s, you'll see one flag prominently displayed far more than any others--the stars and stripes. So, by that "reasoning", all of the associations ignorant people want to make with the battle flag would be made with the stars and stripes.
In addition to the foregoing, it's also sad that people have such utter lack of respect for private property rights these days. No one has a right to tell you what you can and can't put on your property (unless you give that authority to a property owner's association, but that's another matter). What kind of person would want to live in a government that wanted to govern the lives of people to such an obscene extent?