A lot of people probably don't even realize they're doing it. This stuff is drilled into our heads from the time of our very earliest memories. Red versus blue, the farthest two things can be apart from each other while still being the same sense to us (visible light).
When you're a kid it's blue toy aisle versus pink toy aisle. SEGA (blue logo / mascot) — or I guess Playstation these days — versus Nintendo (red logo / mascot). Coke versus Pepsi.
As we reach adulthood we're primed for duality in a way that makes us think we must choose one way or the other when presented some choice we didn't even ask for. Do I shop at Walmart, or Target? Do I vote Democrat, or Republican? Do I watch CNN, or Fox? Do I use iPhone, or Android? Do I take the Blue Pill, or the Red Pill? By the time one has been coerced into the decision they've already lost. The only winning move is not to play :)