Hardly. Legal immigrants are by far more likely to embrace American culture and celebrate our holidays than those stealing their way into the U.S. The liklihood is greater, in part, because they have some family base attachment to America through marriage, etc.. unlike a border hopper. Those stealing into the U.S. naturally will less likely attempt to assimilate for fear of apprehension - but will flock with their own covey, shunning American culture.
In LA County there are hundreds of thousands of illegal aliens who have been in the US for years. The kids are legal, only because they were born here, but Mom and Pop are not legal.