The settings for Conditional Formatting don't allow for what I want: a simple two-color scheme - positive all green, negative all red.
Even turning off the auto-generate and putting 0 for the midpoint, AA still calculates ranges based on values. Here, the highest value, 6,443 is so far above the others that it assigns it green, but then plus 36 and minus 36 have the same color because they're relatively closer. Setting the max, mid, and min values to +1, 0, and -1 gets closer to what I want, but still shows plus 6 and minus 4 values as the same color. This is trivially easy to do in Excel....