Wearing a Confederate flag should be as intolerable as wearing a swastika.
Celebrating Robert E. Lee is like honoring Erwin Rommel.
There's a reason the "unite the right" rally organized over the removal of a Lee statue in Charlottesville: he is an ongoing symbol of white supremacy despite the lost cause myth perpetuated by reactionaries.
He was a cruel slaver who sought to permanently entrench the practice. There was nothing honorable about what he fought for and he doesn't deserve the respect of a single person, much less that of the government.
Edit: Some added context for this piece of shit, from an account of one of the enslaved people he inherited who expected to be emancipated upon the death of their previous enslaver as promised:
[W]e were immediately taken before Gen. Lee, who demanded the reason why we ran away; we frankly told him that we considered ourselves free; he then told us he would teach us a lesson we never would forget; he then ordered us to the barn, where, in his presence, we were tied firmly to posts by a Mr. Gwin, our overseer, who was ordered by Gen. Lee to strip us to the waist and give us fifty lashes each, excepting my sister, who received but twenty; we were accordingly stripped to the skin by the overseer, who, however, had sufficient humanity to decline whipping us; accordingly Dick Williams, a county constable, was called in, who gave us the number of lashes ordered; Gen. Lee, in the meantime, stood by, and frequently enjoined Williams to lay it on well, an injunction which he did not fail to heed; not satisfied with simply lacerating our naked flesh, Gen. Lee then ordered the overseer to thoroughly wash our backs with brine, which was done.
State courts in both 1858 and 1862 denied Lee’s petition to indefinitely postpone the emancipation of his wife’s enslaved people and forced him to comply with the conditions of the will. Finally, on December 29, 1862, Lee officially freed the enslaved workers and their families on the estate, coincidentally three days before the Emancipation Proclamation went into effect.