It's not that you don't need it, it's that you haven't used it in the past, have had acceptable results, and now think you don't need it. Secondly, it's not a reccomendation, it's a mandate. The verbiage is rather clear. Requires means must, not just if you want to, if you feel like it, or if you haven't broken something in the past going without.
SO, YOU do whatever YOU want, but please don't advise others on a public forum to go against the owners manual requirements. You are advising them to NOT adhere to explicit instructions given by a manufacturer on how to properly setup a towed vehicle. This is opening up anyone who chooses to listen to a whole litany of safety and legal ramifications. Your anecdotal experience, while valid and useful, is NOT a replacement or substitution for the owners manual.
Comfort with risk has been discussed in numerous other threads, and clearly anyone should take what they are told on the internet with a grain of salt, and make their own decisions. However, a direct contradiction to the owners manual specification is reckless at best.