What created anchor babies was construing "and subject to the jurisdiction thereof" liberally, so as to include everybody, including foreign invaders (or at least illegal aliens), and excluding only diplomats, who have immunity from court process but can be expelled (so even diplomats are subject to some jurisdiction).
There has to be some connection between citizenship and birth on the soil, otherwise the nation just disperses. If the world was pure jus sanguinas, the notion of "nation" would eventually become meaningless, as people and blood lines disperse.
And so, defending jus soli is defending the nation, as a defined place on the earth. Perhaps you find that to be a bad thing.
No, I don't consider jus soli a bad thing. I do consider naked jus soli a bad thing. I think that jus soli is a consideration to be weighed along with other factors.
I agree with Vattel who advocated the primacy of Jus Sanguinis. But sure, weight must be placed on the place of birth. But is can not be a disqualifying factor in the presence of jus sanguinis citizenship.