America: The Melting Pot?

The United States has always prided itself on being a melting pot. Immigrants form all different races, cultures and backgrounds all seeking new opportunities and freedoms that they haven't received before. In the beginning the melting pot mainly consisted of white people from different nations and religions in Europe. This notion that all these people of different cultures could work together under the same government was and still is very special thing. If you weren't a part of the King's church in England you could have been jailed or executed even. Even today some countries still persecute people for being different. Today people have more rights and freedoms then they have ever had. Slavery is illegal, racial discrimination is illegal, gay people can get married in some states. We are living in a very progressive time. Even though things may be against the law it doesn't mean people don't discriminate. Today there is a lot of racial discrimination and stereotypes against the Mexican people. Arizona made the "show me your papers" law and the stereotype going around is that Mexican people are here illegally and that they are cheap labor. What happened to the America that offered freedom and opportunity to anyone who has hope and works hard? Now not everything is black and white because there is a valid argument from the other side's point of view.  There is a large amount of illegal immigrants living in the country not paying taxes and just having children here so they become citizens. I'm not siding with any side of this argument I'm just saying things have changed and so has our "melting pot" philosphy.