The love of horses and riding comes from the heart not from the scale. Most heavier riders, have horses that make them look good.
It is so hard when the King of H/J always speaks about the riders size. I left a clinic as an auditor, one day due to the verbal beating the clinician was giving one rider about size. I have been a professional for over 40 years
I am always concerned more about the horse when I see a rider who is too large for his or her mount. If the 20% "rule" is correct, then there are many larger riders who need a bigger bodied horse that can safely carry the extra weight. Horses' welfare first!