One more thing. Ulcers in the duodenum can cause bright red blood. If your doctor didn't use a side view endoscopy unit, he may have missed this. The duodenum can be difficult to see 100%. This is one thing that will cause bright red blood. You probably know that the closer the bleed is to the anus, the brighter the blood. The higher the bleed, the darker, with the exception of duodenal ulcers. I hope this helps, I know your frustrations.
Were you checked for hemorrhoids? They cause bright red bleeding but not that often. Your doctors are at a loss and instead of referring you to someone else, they are telling you that the bright red blood is nothing to worry about! I would call the AMA and ask for the top GI in your area, you need someone who is more knowledgeable. I've been thru this with my son, thinking his doctors were doing everything they could...they weren't. I lost my son. This is not to scare you, just make you realize that not all doctors are good ones, please get a second or third opinion on your problem. It was a fourth doctor who told why and how my son got in the condition he was, and it didn't have to be, but it was too late for him. Get other opinions, something is obviously not right. Take care....