What is the point in having such _days_? Consequently, shouldn't we also have a Scientists' day, an Actors' day, a Plumbers' day, blah blah? Everyone has a place in the universe. All we have to do is never to forget our true calling.
That's the heritage of Soviet Union, where people of labor were the cornerstone of ideology. Consequently every profession got the day to celebrate. I haven't seen it in any other country.
It varies country by country, but I'm pretty sure you'll find various aspects of humanity being celebrated on specific days (women, father/mother, workers, and so on), sometimes even at the UN level (i.e. theoretically worldwide). The point is to get mainstream attention to the achievements and problems of specific and necessary roles which would otherwise be mostly overlooked.
In some cases the celebration is named after the activity (e.g. fighting cancer), but meaning is exactly the same -- would calling it "Programming Day" suit you better?
Those days do exist, eg. Plumber's Day is April 25th.
They are taken about as seriously as Programmer's Day in most of the world (ie. not much, most people have no idea they exist, even people in that profession).
