McJobs aren't going to get outsourced.
However, if illegals get hired there, it damages the labor market for teenagers, many of whom are working part time for extra spending money or for bills.
When I was in High School I has a few friends who worked there, though Micky Ds isn't known to hire illegals, at least over here.
But other jobs that can't be outsourced but can be given to illegal labor thus damaging American Labor or Native Labor are custodial work and many numerious physical intensive on the spot types of work.
Is McDonalds, a world-wide corporation, just the jobs we see from the front counter? No, there is a lot more going on than just a few front counter jobs. For example, where do they get the materials for their famous sandwiches? How do those materials get to the various resturants around the world? Do they still run those TV ads? Where do those come from, and how are they paid for?
And that's where part of the culture change comes in. Those teens can no longer find the part-time menial but educational work so instead they spend their time _________? (fill in the blank with whatever fills the time of bored teens these days) How do they learn about the real world, find out what it's like to work for a living, if all those 'jobs that Americans won't do' are taken by immigrants? And while you're at it, kid, he's not only taking your place in the entry level job market, he's overtaking your language. Por Espanol...press 1, for English...press 2.
What I'm trying to say is we may be helping to lift up Mexico from its Third World Country status but it's being done at the expense of America being brought down. (Quite similar, actually, to 'bringing democracy to the Middle East' and other parts of the world while allowing socialism to creep into our own country, isn't it.)