It’s certainly not incorrect, these are not infinitely thin lines. The original line is 100 pixels long and 1 pixel wide. A diagonal stair-stepped line of 70 pi

It’s certainly not incorrect, these are not infinitely thin lines. The original line is 100 pixels long and 1 pixel wide. A diagonal stair-stepped line of 70 pixels is an average of about 0.7 pixels wide, which is why you’re deleting about 30%. You need to mush the additional pixels in somewhere between the stair steps to make it an average of 1 pixel wide again.