Indeed they were. And turning someone away because they are in violation of a law the government itself doesn't even feel like enforcing is breaking the intent of the Gospel.
If the government doesn't want Mexicans worshipping in American churches then the government should commit appropriate resources to preventing Mexicans from entering the US.
Criticizing churches for treating sinful human beings like fellow Christians is laughable.
Are churches supposed to check papers at their doors? Should churches investigate all their congregants to make sure all of them are compliant with the tax laws, that they are not wanted on any outstanding criminal warrants in other states, etc.? Should Bernie Ebbers' pastor be sued for receiving illegally-obtained funds in his collection plate?
If the government wants pastors to be pol;icemen then they should pay them a policeman's salary.
Until that happens, blame the government, not the churches.