The simple fact: young people are faced with the ongoing barrier of needing a level of experience to obtain that target career they have struggled to gain qualifications for.
In light of this the interaction between large numbers and a wide cross section of different people is a fair reason to begin in a McDonalds restaurant. You do not have to want to make Mcdonalds your life but here is a company that teaches people about dealing with customers, children, hierachy and ongoing systems that we meet through our life.
The fact remains that young people find that have some form of work experience, whether it be relating to their field of choice or not removes or certainly helps remove that barrier to get to that next job.
Secondly, I doubt whether finding a job start in a computer company is that easy for an 'unskilled individual'. I'd say your friend has done well for him/herself and good on them. However the abundance of this field offering the numbers of positions for unskilled people would be well short.
So on this note : those whose have chosen McDonalds ( or KFC for that matter ) have taken the first steps to overcoming a barrier that exists between them and their ideal profession.
Keep moving forward