It's the lack of a critical thinking in a certain segment of the people who are susceptible to the fear and hate mongering of the NRA-owned politicians. They don't represent the majority. The overwhelming majority WANT sensible gun control. We don't want military-style weapons in the hands of civilians at all. But, those politicians don't need the majority. They've so radically gerrymandered voting districts that they've disempowered the overwhelming majority.
Did you know that all the red states combined in America, their Congressmen and congresswomen represent less than 20% of the actual population? And, in those red states, the core conservative base of those states represent less than 10% of the population. But, those red states carry outsized electoral power. In real citizen numbers, even in those "red states," moderates, liberals, and progressives outnumber conservatives – in those states, it is minority rule.