Why? Why should someone be a citizen because they were born in a specific country? With jus sanguinis things are much clearer: one of your parents is a citizen, you're a citizen. Your kids are citizens. In perpetuity.

Jus solis is a bit like right of way at American intersections: the person that's been there the longest goes first. Whaaaaaa? What if two cars arrive at the same time? What if 4 arrive at roughly at the same time? What is people can't agree who arrived first? A lot of the rest of the world gives way to the car coming from the right. Which is obvious and basically non-negotiable.

Similar idea here.