Separating parents from their kids is one thing. Neglecting kids and denying them water, food, and not facilitating any form of basic hygiene is another thing.
Children covered in lice, bodily fluids, without showering for weeks to months. Newborns being taken care of by 5 year old detainees with no relation. They are denied food and water. They are forced to drink water from toilets. They're scared to ask for food and water [1].
Then, let me introduce you: The Mexican Repatriation Act of 1929.
If your argument is that citizens need to be protected, I remind you that in 1929, the US government took US-born children of Mexican heritage (technically, US nationals), put them in buses, and sent them to Mexico. In total, up to 4,000,000 Mexicans and their US born descendants were victims of this.
It is possible that some the families being detained and separated are descendants of US citizens. But nobody cares, you know why? because it's not about citizenship and immigration. It has never been about that. It's about making bullshit excuses for racism and ethnic cleansing. Before the Mexican annexation it was done to the Native Americans, and for them there were other excuses as well.
The US has set a strong precedent about not giving a flying fuck about borders, immigration and sovereignty. What did American immigrants in Tejas, Mexico do? or Alta California, Mexico? or the Kingdom of Hawaii? or countless other territories? They were given land grants and instead of being grateful, they revolted, declared independence and then joined the Union because they were not allowed to have slaves, or because they saw themselves as entitled to those lands. Lands that they had no connection to whatsoever.
Before the US existed, their predecessors, the British empire, had other races to discriminate. Basically every other nation including other nations in the British Isles. That mentality led them to invade 99% of the planet and kill millions of people through wars, famine, etc.
In contrast, the ancestors of the families being detained are the populations that have inhabited North America for 10,000 years. Not a couple of centuries. 10,000 fucking years.
[1] https://youtu.be/mRUxDNE8uzc?t=36