Some of it might be deserved (the Bush years done incredible damage to the reputation of the US) a lot of it is not, and this is coming from my multiple experiences over the years of visiting almost every one of the lower 48 states.
As for Texas its probably one of my more favourite locations in US (behind Arizona, Utah and Georgia), these Norwegians should stereotype less and travel a bit more they be in for a pleasant surprise and the place aint that crazy ;)