So homosexuals put in prison because homosexuality is illegal in places (including the US not even 20 years ago)... no sympathy for them? OR... do you think not all laws are equal and that there are bad laws?
For bad but constitutional laws, we have a process for challenging and changing them. While they're in effect, I believe that if you're going to break them publicly, you should not expect to escape consequences.
Back when the U.S. constitution was written, visas did not exists, and getting permission to immigrate was uncommon. You could literally walk into most countries without any papers. As such, the enumerated powers of Congress actually only contains the power "To establish an uniform Rule of Naturalization" (Article I, Section 8, Clause 4). Nothing about restricting immigration.
The US did not regulate immigration at all until the passage of the Chinese Exclusion Act (1882). The Act was challenged in the courts, and the SCOTUS ruled that Congress' power to "To establish an uniform Rule of Naturalization" meant that it could also exclude people from entering the country – which is quite a stretch. For more, see: http://openborders.info/blog/immigration-
Popular opinion at the time was that Chinese and other Asian people were unfit to be part of American society, and the SCOTUS was willing to stretch the meaning of those words in the Constitution to grant Congress the new powers necessary to exclude them.
The problem is that a law is or is not constitutional based on numerous other factors such as popular opinion. The truth is that the SCOTUS is partially impacted by the will of the people at any given time (to say nothing of the entire issue of the political nature of the SCOTUS). Crying foul is one way to modify the will of the people. In some cases, what is constitutional is even explicitly tied to external factors (such as obscenity tests which in part depend upon current morals of the community).
If they did mean to create different laws they felt differently about, I left them an opening to do such in my last question.