There is no honest scholarship that says that children of illega are just like the children of diplomats. An illegal is subject to our laws. If he breaks a law, he'll be tried and punished like everyone else, he's subject to our laws. A diplomat however, enjoys broad immunity to our laws.
Didn't the USSC rule in Medellin v. Dretke that Jose Medellin was not subject to the same U.S. laws as everyone else and he had extra rights vis-a-vis his illegal status in the country? The fact is Medellin was not treated the same as everyone else or he would be on death row except for the USSC decision.