This is one of the biggest reasons I've found that when getting into the larger snakes for the first time you should start off with neos. If you jump right into getting one that is already 4-5' long then you really have no control over how it was raised or handled previously, thus can end up with a really pissy large snake that can do some damage.
I purchased both of my rtbs as babies and neither of them give me any attitude. And at 8' and 20 lbs for my largest rtb I am very glad of that because there is no way someone of my size could handle a snake that large going crazy on me.
So I wouldn't necessarily let these current rtbs turn you off of them completely. But maybe consider starting off with neos and raising them up yourself so you can actually control them and end up with large docile rtbs rather than psychotic hissy ones.