The entire point is selecting the lesser of two evils.

If you choose to eat strawberry ice cream instead of dog poop, that’s not selecting the lesser of two evils.

If you choose to eat bugs instead of dog poop, that’s where you’d refer to it as the lesser of two evils.

Having an objectively good option and an objectively terrible one isn’t choosing the lesser of two evils.

Having a terrible one and a slightly less terrible one is.

You are correct that we shouldn’t need to be choosing between the lesser of two evils, but that phrase only really applies when both options suck.