The story is a bit misleading, as he does not appear to be a Microsoft employee as such.
There are a few things to note:
1) It's unclear whether this MSCopy print company comes under the Microsoft umbrella or is totally independent.
2) None of us knows what the terms and agreements between this company and Microsoft are regarding security issues - seeing as it is a Microsoft campus.
3) We don't have any idea what his terms of employment were regarding security issues.
4) The guy was a temp, technically employed by his agency rather than the printing company. This makes quite a bit of difference in whether he's able to sue anyone for wrongful dismissal or not, at least in the UK.
It's all a bit silly though, and hardly newsworthy. ;-)