First; the US is not a democracy. We're a representative republic. We do not do "mob rule" as evident, in part, by our use of the Electoral College to choose our Chief Executive. This was done intentionally and works well. The people of California and New York cannot impose their political will on the rest of the country.
Second; what gives an immigrant, illegal or not, the right to put one foot in my country and immediately be eligible for taxpayer-funded benefits? When my great-grandparents immigrated to the US they had to sign paperwork agreeing that they wouldn't be allowed taxpayer-funded benefits. They had to have employment lined up or the ability to be self-reliant. They had to pass a medical exam. They had to be able to speak, read, and write English. They had to be willing to invest themselves in this country and its ideals. Now all they need to do is, somehow, get across the border and/or pop out a kid here and they're golden. They're not invested in this country nor do they intend to be. They don't give a damn about the US except for what they can vote away from the American taxpayer.
I'm a native Californian. The vast majority of immigrants (legal and otherwise) here come from the third-world and speak, exclusively, any one of thirty-plus languages. Few speak English or are educated. Most are illiterate, even in their native language. They band together in balkanized communities and make them into their own little countries. Go there as an outsider and you're at risk.
Our schools and hospitals are overrun. My grand-kids can't get a proper education because teachers are busy trying to teach in multiple languages. Our crime rate is high. Our taxes are sky-high with the largest chunk of those taxes going to "immigrants" by way of taxpayer-funded benefits. Of course California, having a progressive Democrat super-majority, loves this because it buys them votes. Who cares about the California citizen? California hasn't been the "golden state" for a long time. I will be retiring in a few years, leaving this cesspool to live in a free state.
You can bleat your bleeding-heart BS all you want. The citizens of the US are not an ATM for anyone setting foot here. This rule is a good first step. It needs to be followed up with more. A lot more. And it can't be done soon enough. No matter what the BS artists in SF tell you.