One thing its writers provided (wisely) was a process to amend it. Your examples clarify the need for that. We simply cannot have security at home if non-citizens have so many rights. It's obvious that no one group can be targeted; the precedence of these laws will protect them
I really don't understand why people are using the argument "we're all immigrant children". My ancestors came here when there was a need, in a growing country, for farmers, laborers, and factory workers. That need no longer exists.
The other point is that when my ancestors arrived, entering the country and becoming a citizen was a rigorous procedure. That is hardly the case now, and that is why it has gotten out of hand. At this point, what we need to do is stabilize our population, for security, cultural/language, matching jobs with opportunities and the the environment. I just don't see how we can have security with the status quo on entry into the US without severe curtailment of our freedoms.
That's part of the discomfort with the Homeland Security Act. A lot of measures are being taken which will quite probably cause a loss of freedoms and more surveillance of law-abiding citizens and present a real danger to our futures in the hands of the wrong officials. A lot of this could be avoided if those in charge identified the real problem and solved it. That problem is that people who want to destroy the US and everything we represent can pretty much enter the country at will.