If I'm reading you right, you're saying if one country does something bad, that makes it OK for another country to do the same? You can likely find a country in the world doing any heinous thing you can think of, so is everything on the table? What about positive things? Lots of countries have socialized medicine, so by your logic doesn't that mean the US should, too?

And if you think activism is bad for non-residents (non-citizens?) who do you think should decide what constitutes activism? A student goes to a pro-Israel rally, is that deportable activism? A tourist goes to an 'adopt-a-puppy' event at a no-kill shelter and donates $10, is that deportable activism?

Non-citizens have constitutional rights as well. The DHS having the ability to produce subpoenas without judicial oversight is definitely a bad thing.