Pretty much everything?
If some new country like South Sudan was picking a rule from scratch, one could perhaps convincingly claim to be against jus soli for reasons other than racism. But to push for a constitutional amendment to deny citizenship to babies that are American in every way betrays the obvious reason for doing so. It just doesn't fool anyone.
Just sounds like you feel very strongly about this and want to say "everyone who disagrees with me is racist".
The majority of the world's population lives in countries that don't do birthright citizenship.
Jus Soli definitely gets abused. Cheap international flights didn't exist in 1866 when birthright citizenship became part of US law.
I could see merit in amending those laws, perhaps not abolishing it but maybe tightening it to only apply to children of legal residents or something like that. That's a system that many countries use, including progressive European states.
https://en.wikipedia.org/wiki/Literacy_test
The argument that a rule is color-blind on paper doesn't make systems that are incredibly racist any less so.
The jus soli repeal is a constitutional amendment that's colorblind on paper but that furthers a racist outcome in practice, which is why it's being promoted by bigots.