Besides, that article is bullshit. IMO.
If you're salaried and your salary is on a per annum basis, I doubt you'd find any contract which stipulates how many days in a year that covers. You're still working your normal hours per week. It's not like they added an extra day with a whole new name or anything.
Anyway, you could view it from the other side too where the employer is getting ripped off a day for every year which doesn't happen to be a leap year.