A lot of the teachers that I have worked with and met in the past have been very resentful of my bilingual students because of their immigration status (whether or not they are illegal...we're simply not supposed to ask). Some of my students are quite legal and have all of the documentation to back it up. On the other hand, some of my students come in to school frantic because Immigration Enforcement Officers were at their favorite grocery store last night and nobody is quite sure whose families are still in tact.
The first argument I will address is a simple one: "Everyone who comes to this country should learn English!" Well, dear friend, learning is a process. I did not learn Spanish overnight. As far as I know, every single one of my students is working on learning English and a huge percentage of their parents are too. But why doesn't every adult in the US learn another language? Oh yeah, because it is HARD. It takes time and studying (and often money to enter yourself into academic program). Of course every person who is in this country wants their life to be easier, and learning the common language makes life SO much easier. So they are trying, I won't believe you if you tell me they're not.
The second argument: "They are ruining the economy." To this I will simply ask, did your parents let you chose where you wanted to go and what you wanted to do when you were a child? These students have NO SAY about what country they live in. If you asked my students today where they'd prefer to be, you better believe they want to be in Mexico, to be home. But the ones that are ok with staying know that their parents are doing everything they can for a better life. They have more opportunities, more money, and better living conditions than they had in Mexico. I think any good parent would risk their lives to save their children...that is exactly what illegal immigrants do, risk their lives to make their children's lives better/safer/more successful. But simply put, students do not deserve to be mistreated because of the choices of their parents. They are still people and human decency dictates that you care about them like you would any other child.
The third argument: Teachers will often complain, "trying to modify and devote all my extra attention to these children is too hard." I'm not saying it is not hard. This is what I do for a living and it is an uphill battle every day. But if you think about it, whose life is actually hard? How about the student who walks into a classroom full of people he/she can't talk to, who keeps his head down every day in the hopes that he can understand enough not to make too many mistakes, and definitely fade into the background enough so that they're not made fun of for being so obviously different. All I can do is offer a safe harbor for these students, to make their transition as easy as I can in an already impossibly difficult situation. I don't resent these students, my heart breaks for them.