- The states have different demographics, because neighboring each other does not mean similar demographics(see PA vs NJ, AZ vs NM, UT vs CO, or NC vs SC)
- Huge influx in ND of energy workers who are scared of the liberal Dems enacting environmental regulations, and/or climbing through their windows at night to eat their small children
- Tester is male
- Tester is male
- Tester is male
- Tester's haircut
- People are afraid Heitkamp has no soul because gingers
They actually do have quite similar demographics,
see here, the main differences between the states are median income ($59K in ND vs $48K in MT) and North Dakota being more Republican.
But the rest of your points are solid.