I've never found bicycle riding to exacerbate hemorrhoids. Where they are isn't where a butt contacts a 'regular' bicycle saddle. The padded saddles make it worse because they contact almost every part.
I eat more than 3 pounds of fresh vegetables and fruit every day (I'm a vegan), make my own bread, have recently added psyllium seed husks, drink at least 2 liters of water. I walk at least 3 miles every day. Why I have them - it's a mystery. I'm 68.
They're dynamic: something makes them happen. A physician can treat them (never had it done) but if the causes persist they will come back. Hippocrates prescribed hot pokers, encouraged the victim (er - patient) to scream because that will make them more prominent.