I agree. I have no idea why the 8SL tow-prep wiring is listed on the 28i but is not listed on the 35i. We have installed the OEM tow harness on many 35's and the factory connectors were always present and functional.
Also, if you plan to only use the hitch for a bike rack and not for towing, you may want to consider unbundling the hitch kit. We sell the invisihitch separate from the OEM harness for exactly this reason. It saves you the cost of the harness and the reprogramming fee.