Unfortunately, this is similar to "What came first? The Chicken or the egg?"
Having worked in the colonoscopy lab for a number of years I have had several patients complain of hemorrhoids after a procedure as the prep is certainly harsh and irriating to say the least.
As the tech was a bit rough and combined with the prep and constant running to the bathroom, this is the ideal scenario for a hemorrhoid to occur.
The causes of hemorrhoids include genetic predisposition (weak rectal vein walls and/or valves), straining during bowel movements, and too much pressure on the rectal veins due to poor posture (it is well known that hemorrhoids are very rare in nations where people squat to deffecate) or muscle tone. Constipation, chronic diarrhea, poor bathroom habits (sitting for unusually long periods of time [e.g. reading on the toilet] or excessive cleaning attempts), pregnancy, postponing bowel movements, and fiber-deprived diet can also contribute.
I have to say it was a combination of both the procedure and the prep, leaning toward the roughness of the tech as a definite contributing factor. Unfortunately, this is also a no win situation. The physician will undoubtedly say that you were predisposed.