You make excellent points, and even though administrative costs have increased dramatically over the last few decades - before the colonization of America by illegals, our healthcare and hospitals didn’t have an overwhelming issue with cost containment from the un-insured.
Illegalism has no positive impacts on our society except perhaps lowering the price of meals in Mexican restaurants. The costs of illegals overwhelms educational facilities, health care, law enforcement, increases the price of housing, increases the ability of the cartels to undermine the rule of law. These prey upon the illegals through extortion, blackmail and intimidation.
Then there are the incidental costs of drunk driver smashups, the deaths in such smashups. Increased insurance costs for everyone. I’m sure you can add to this list.